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Medicinteknikdagarna
Stockholm, 2013
ABSTRAKT
Egentillverkning, ansvar, hur och vem?
Session 1B
Moderator: Heikki Teriö
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Egentillverkning – En viktig del av innovationsarbetet
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Jimmy Johansson , Maria Olsson , Lisa Nilsson , Thomas Hajdu , Jörgen Larsson , Anna Grahn
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Medicinsk teknik, Skånes universitetssjukhus, Lund/Malmö, Sverige. Bild- och funktionsdiagnostiskt centrum Lund, Skånes
universitetssjukhus, Lund/Malmö, Sverige.
Inledning
Möjligheten till tidig klinisk användning av medicinsktekniska produkter är ett viktigt verktyg i landstingens
innovationsarbete. Att tidigt kunna använda egentillverkade produkter i begränsad omfattning ökar sannolikheten för att det
är slutanvändarens behov som styr utformningen av framtidens produkter. Positivt resultat från den begränsade kliniska
användningen ökar produktens trovärdighet längs den ofta krokiga vägen genom olika innovationssystem och minimerar de
ständigt återkommande frågorna om hur vidare det finns ett reellt behov eller ej.
Bakgrund
Medicinsk teknik vid Skånes universitetssjukhus har sedan ett tiotal år tillbaka arbetat med egentillverkning inom elektronik
och finmekanik i stor utsträckning. Det har funnits rutiner och mallar för riskhantering och uppfyllandet av väsentliga krav
men det har saknats fullständiga processer för t.ex. produktutveckling samt en övergripande kvalitetsmanual.
Under åren 2008-2011 ökade antalet projekt inom medicinteknisk mjukvara avsevärt och arbetet med att hitta effektiva
metoder för detta inledes. Vi uppmärksammade att de flesta regulatoriska aktiviteterna genomfördes precis innan
driftsättning, vilken inte bara ger en obalans i arbetsbelastning utan även minskar möjligheten att förbättra produkten utifrån
t.ex. riskanalysens resultat. Vi såg därmed över ordningsföljden för de övergripande aktiviteterna och framförallt
riskhanteringsprocessen som ofta förbrukar mycket resurser. Under arbetet med att skapa effektivare processer för
riskhantering och användbarhet använde vi ett projekt som tog fram en applikation för beräkning och presentation av
blodflöde i hjärnan som pilot där en professor och två doktorander från Lunds Tekniska Högskola följde och studerade
analysarbetet. Resultatet har publicerats i tre artiklar1,2,3 och använts för att förbättra processerna för riskhantering och
användbarhet på Medicinsk teknik.
Utveckling
Till följd av att Medicinsk teknik utökat sin verksamhet inom forskning och utveckling och nu leder eller medverkar i
flertalet stora forsknings- och utvecklingsprojekt har det varit möjligt och tvunget att lägga ännu större fokus kvalitetsarbetet.
Nyligen har upprättandet av ett fullständigt kvalitetsledningssystem för utveckling av medicintekniska produkter enligt ISO13485 avslutats. Detta arbete gjordes stegvis genom inledande utbildningsinsatser inom vår verksamhet, därefter i form av
praktiskt genomförande i mindre skala samt analys av ett företags ISO-certifierade ledningssystem. Slutligen upprättade en
mindre grupp bestående av processanvariga och slutanvändare ett fullständigt ledningssystem som ska passa väl in vår
verksamhet. Ledningssystemet innehåller alla tillämpliga processer men pekar i så stor utsträckning som möjligt på befintliga
rutiner inom verksamheten. Processen för användarvänlighet och utveckling av medicinteknisk programvara, enligt EN
62366 respektive EN 62304, har t.ex. använts inom det VINNOVA-finansierade projektet ”IT-stöd för Avancerad
Cancervård i Hemmet” där stort fokus lagts på användarvänlighet och det har genomförts aktiviteter med både vårdpersonal
och patienter.
Det fortsatta arbetet med ledningssystemet på Medicinsk teknik kommer inrikta sig på att lägga respektive projekt på korrekt
nivå samt att utbildning av berörda medarbare sker i den takt som krävs.
Resultat och slutsatser
Ledningssystem ger universitetssjukhuset kontroll över egentillverkade produkter och öppnar upp för innovativt arbete i flera
olika projekt. I projektet ”IT-stöd för Avancerad Cancervård i Hemmet” har flera mindre delar av det medicintekniska
systemet tagits i kliniskt bruk. I flera fall har den kliniska användningen endast varit ett mellansteg för att få feedback för den
framtida utvecklingen. T.ex. används teknik, som i framtiden är tänkt att flyttas hem till patienterna, kliniskt inom sjukhuset.
Det kan även handla om begränsad användning där man har bra kontroll på utbildningsgrad osv. Därmed kan man på ett
säkert och relativt tidigt stadium få återkoppling på produktens utformning och prestanda från tänkta slutanvändare.
Medicinsk teknik verksamhet inom forskning och utveklings stödjer även regionens innovations- och testbäddsverksamhet
med detta arbetssätt, vilket med stor sannolikhet medför att fler och bättre produkter når marknaden och därmed tillgodoser
fler användare och patienters behov.
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"A Case Study on Software Risk Analysis and Planning in Medical Device Development"
”Introducing Usability Testing in the Risk Management Process in Software Development”
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"A Case Study on Software Risk Analysis in Medical Device Development"
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Ehälsa/IKT I
Session 2B
Moderator: Bengt Arne Sjöqvist
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2B2
E-Health in Developing Countries to Manage illnesses through Patient Education and Empowerment of
Rural Health Workers
Mannan Mridha1, Björn Erik Erlandsson1, Mohammad Islam2, Mandalika B. Srinivas3
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School of Technology and Health, the Royal Institute of Technology, Stockholm, Sweden
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BSM Medical University, Dhaka, Bangladesh
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Birla Institute of Technology and Sciences, BITS, Hyderabad, India
1 Introduction
In developing countries, the vast majority of the people are living in the rural areas with limited access to quality care. In fact,
village doctors with limited training, community health workers, unqualified allopathic providers and drug store sales people
are largely responsible for providing the rural medical care. Severe sufferings and increased healthcare cost of the patients are
caused due to either inadequate information, choice of drugs and treatment strategies etc. Some relatively well to do rural
patients go the cities for medical care. The private hospitals and clinics offer adequate services but are out of reach for the
common people. The government hospitals and clinics are affordable for all but offer poor quality services. Most of the
medical equipment are imported but often do not function effectively due poor quality of service and maintenance Physicians
order expensive and sometimes unnecessary investigations because they receive incentives for their referrals from the
diagnostic centers. Doctors' tendency to prescribe fashionable and expensive drugs or irrational drugs with limited
therapeutic value is also of concern for patients’ care and safety. Currently a burning question is how to bring a rapid
improvement for rural people in the developing countries that have no or limited access to safe health care? The application
of Internet and Communication Technology, ICT in healthcare is growing rapidly in an attempt to find cost effective
solutions for providing quality healthcare (1). We are working with the integration of smart, affordable medical devices with
telemedicine using modern ICT tools, for improving the rural health care situations (2).
2 Method
The rural people depend on village doctors and paramedics. But they have limited capacity for providing relevant healthcare.
In order to improve health care facilities and achieve health equity and patient safety, we together with the local partners are
using Innovative, Relevance, Acceptability, Affordability and Effective ICT tools to address some of the health problems in
rural areas. We are working to improve rural health workers’ capacity, quality and performance by creating enabling
environment to provide services that are. Our actions include development of a) reliable, robust and cost effective medical
devices, b) proper education and training to use the diagnostic equipment, c) connectivity to the medical experts for disease
prevention and treatment advice and d) health education to teach how to prevent and treat health problems which routinely
afflict them. We have developed and deployed reliable and affordable diagnostic devices integrated with the communication
systems and have developed care services nearest to the homes that have the capacity to diagnose the common chronic
illnesses, formulate in consultation with distant specialists a Home-care Plan, follow-up care, identify secondary risks and
make referrals. We have also initiated to organize Health Clubs to create scope for collective approach for management of
these illnesses that ensures access and patient education and empowerment. Female health worker are visiting rural women at
the homes with: i) relevant and user-friendly health care content to educate to manage health, ii) portable and affordable
diagnostic and iii) communication platform to connect the health workers and patients with medical experts for advice.
3 Results
We find our model of e-Health activities to be appropriate for India and Bangladesh and believe to be suitable for other
resource-constrained countries. Rural people find great satisfaction from the face to face video-consultation with the medical
experts. They appreciate the just in time, cost-effective and quality treatment without any need for travelling. This has greatly
reduced the earlier errors due to wrong diagnosis or wrong medication or too much medication for a too long time. Some
other positive impacts of our work are: a) Better monitoring of the progress of health programmes and achievements of health
MDGs. b) Increased understanding of the importance of e-Health by the policy-makers c) Rural doctors and paramedics
benefit from a satisfying professional experience thanks to connectivity to medical experts and avoiding harmful mistakes.
This rural e-Health service decreases their professional isolation, reduce number of unnecessary referrals and facilitate for
continuous education and empowerment, d) A creative environment of health around the Point of Care to strengthen the
confidence of the community for seeking health and start sharing the responsibility of health care by all stake holders;
4 Discussions
While working with ICT tools for empowering the rural people in Bangladesh and India, some of the challenges that we
faced include, unreliability of electricity supply, weak internet backbone, high internet access cost, financial constraints
preventing the purchase of an appropriate number and type of ICT equipment, unavailability of adequate number of
computer-literate employees to implement e-health programme, resistance to changes. Work should be intensified to: a) raise
awareness of existing e-Health tools and services, b) develop an knowledge exchange network to share practical experiences
on the application and impact of e-Health initiatives, c) create an e-Health information resource to support the needs of the
rural people and d) promote the use of e-Learning for rural health workers and rural people.
Acknowledgment: This work was financially supported by the Swedish International Development Agency, SIDA.
References
[1] Chandrasekhar, C.P. and Ghosh, J. “Information and communication Technologies and health in low income countries:
the potential and the constraints”. Bull World Health Org 79(9): 850-855, 2001
[2] Mridha M. and Pehrson Björn, “To develop a telemedicine system to improve remote diagnoses and to deliver cost
effective, better quality specialist services in developing countries”, International conference on Wide Open Access, 2004,
Stockholm, Sweden.
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2B3
A cross-sectional pilot study assessing needs and attitudes to implementation of
Information and Communication Technology for rational use of medicines among
healthcare staff in rural Tanzania
Jessica Nilseng, Lars L Gustafsson, Amos Nungu, Pia Bastholm-Rahmner, Dennis Mazali,
Björn Pehrson, Jaran Eriksen
In resource-poor countries access to essential medicines, and suboptimal prescribing and use
of medicines are major public health problems. Health workers lack updated medical
information and treatment support. Information and Communication Technology (ICT) could
help tackle this. The impact of ICT on health systems in resource-poor countries is likely to
be significant and transform the practice of medicine just as in high-income countries.
However, research for finding the best way of doing this is needed. We assessed current
approaches to and use of ICT among health workers in two rural districts of Tanzania in
relation to the current drug distribution practices, as well as assessing the feasibility of using
ICT to improve ordering and use of medicines.
This pilot study was conducted in 2010-2011, mapping the drug distribution chain in
Tanzania, including its problems and barriers. The study was conducted in Bunda and
Serengeti districts, both part of a nationally supported ICT for rural development project.
Health workers involved in drug procurement and use at 13 health facilities were interviewed
on use of and knowledge about ICT, and their attitudes to its use in their daily work. They
were also showed a potential ICT tool. This tool was a prototype application for android
tables developed at the KTH Royal Institute of Technology in Stockholm. It consisted of two
parts; inventory of drug stock and drug ordering, based on the Tanzanian Medical Stores
Department (MSD) current paper forms.
Interviewees reported stable drug supply as their main challenge: Drug supplies were often
delayed and incomplete, resulting in stock-outs of essential medicines and equipment. The 20
interviewed health workers all used mobile phones, 8 of them Smartphones that they
connected to the Internet. All were very positive to the drug tracking application, and
expressed a great need and wish for continuous medical education by distance.
New ways to order and distribute drugs, and support their use with updated knowledge are
increasingly needed as soaring medicine costs and chronic diseases add to the burden on
health systems. This makes it important to test and evaluate how simple ICT-technology
integrated into the health-care system can improve the quality of drug ordering, distribution
and use in rural parts of Africa. Studying this in a systematic way is pertinent, e.g. using the
Technology Acceptance Model (TAM).
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2B4
Exploring the potential of mobile phone and web based technology to promote the Sexual & Reproductive
Health of high school aged youths in Zimbabwe
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Comfort Sithole , Leif Sandsjö , Bengt Arne Sjöqvist
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M.Sc. Chalmers Univ. Of Technology. Assist. Prof. Medtech West/School of Engineering, University of Borås. Prof. of Practice, Dept.
of Signals & Systems, Chalmers Univ. Of Technology
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1. Introduction and Background
Telemedicine or eHealth by definition encompasses the communication of health practices via technology, and the advent of
the internet and mobile phone technology brought seemingly endless possibilities for telemedicine. Such technologies may be
instrumental to promote health in hard to engage groups, especially young people, as interventions that make use of the
internet tend to influence young people as they frequently use the internet to find information pertaining to their health.
Generally, youths are put off by more traditional means of engaging with health care services, and this applies more so to
accessing Sexual and Reproductive Health (SRH) services. The general consensus is that most youths appreciate the
anonymity, confidentiality and convenience factors associated with accessing SRH information from the internet.
2. Aim, Method and Results
This work, undertaken as a Master Thesis, is aimed at systematically exploring the potential that is offered by mobile phone
technology in promoting the Sexual & Reproductive Health of high school aged youths in Zimbabwe. Youth SRH services
are sparsely available in Zimbabwe and the exploitation of available and future technologies in youth SRH services has not
been widely explored.
The use of mobile phones in Zimbabwe is on the rise and broadband internet is becoming widely available, thus this
technology can be utilized efficiently to offer services that are aimed at accurately informing the young people of Zimbabwe
about their sexual and reproductive health.
From the research carried out, only 10% of youths had accessed available SRH services, but given that 97% and 86% of
survey participants have access to a mobile phone and the internet respectively, it would suggest that employing an SRH
intervention that exploits this readily available media would be more effective.
Taking into account perspective user requirements and the technological environment in Zimbabwe, the Youth Sex Health
Online (YSHO) web-based SRH clinic and the complimentary Just Ask! Text messaging services were designed. YSHO is
aimed at being a non-commercial one-stop shop for all adolescent SRH needs that meets identified needs in a relevant,
efficient and effective manner.
3. Conclusion
Feedback on the mock-up of proposed services suggests that the proposed service is effective and of particular benefit to its
intended users. This work has shown that eHealth applications offer solutions to existing needs. The need for a relevant and
effective youth SRH service was identified in Zimbabwe, with so many teens seemingly unsure about where to access vital
information about their SRH needs. By making use of web-based and mobile phone technology that is readily available to
these youths, YSHO as an eHealth application offers a solution to the need. Even though the state of eHealth in Zimbabwe is
in its infancy stage, it can be suggested that investing in a national eHealth strategy and solutions like YSHO would
invariably lead to a decrease in state spending in addressing some health issues.
Keywords: Sexual & Reproductive Health, technology in youth SRH services, eHealth in developing countries, web-based clinic, text
messaging service, mobile phone application.
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2B5
M-Health Application Product Development for Physiological Disorders Based on
Interaction Design
Helen Sørheim 1, B.Sc., Ankica Babic 1,2, Ph.D.
1.
Institute for Information and Media Science, University of Bergen, Norway
2.
Department of Biomedical Engineering, Linkoping University, Sweden
Introduction: The paper identifies a multidisciplinary nature of the team work needed to put in place
to reassure project, design and product development that could meet needs of patients and health care
givers and sustain upgrades and future development. The project is focused on patients with severe
conditions such as schizophrenia in which constant monitoring and support is central to the patient
well-being. There are two aspects that the development should follow: self-monitoring in stabile
periods and instant help in cases of crises.
Background: System development is strongly based on interaction design using input of all
stakeholders (patients, patient groups, care givers, health and patient networks). It takes into account
existing healthcare tools (treatment and crisis plan) and well-established treatment approaches which
help utilizing good clinical resources known to all involved stakeholders.
Methods & Expected Results: The Figure 1 presents the product development phases that were used
as one of the development tools besides scientific and clinical ones. Figure 1 includes key activities,
resources, partners and values, customer relationships and segments, channels, cost structure and
revenue streams, which is identified by Osterwalder, Pigneur and Tucci (2005).
Figure 1: Application business model
Discussion: We have studied the business perspective of the application to sustain the product life in a
demanding clinical reality. We have identified the strength of having multiple stakeholders involved
from the very beginning and made the user input central to the application product development.
Literature: Osterwalder, A., Pigneur, Y., & Tucci, C. L. 2005. Clarifying business models: Origins,
present and future of the concept. Communications of the Association for Information Science
(CAIS), 16: 1-25.
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2B6
IT-baserad hemvård av djur med hjärtfel
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Clarence Kvart1, Anna Gund , Andreas Wahl3
2
SLU, Uppsala, Sweden. Chalmers Göteborg, Sweden, 3Karlstads djursjukhus, Sweden
1. Introduktion
Studiens målsättning var att utvärdera om ett internetbaserat system benämt Petheart utvecklat från ”Care at Distance”
(Gund 2008,2011) kunde användas för att förbättra vården av hjärtsjuka hundar och katter. Detta med huvudsyfte att på ett
tidigare stadium kunna upptäcka en hälsoförsämring samt visa om eftersträvad effekt uppnås vid behandling och
medicinering av hjärtsvikt.
2. Metod
Systemet som används i studien är internetbaserat och består av en webportal som kan nås från datorer och även nyare
mobiltelefoner som har tillgång till internet. Genom att logga in på webbportalen med sitt användarnamn och lösenord kan
djurägarna föra in sitt djurs mätvärden angående puls och andningsfrekvens samt svara på hälsorelaterade frågor.
Väl inloggade på webbportalen kan både djurägare och vårdgivare i en spalt till vänster välja att klicka sig vidare till ett
flertal olika sidor. Djurägarna kan här välja fliken ” Lägg in ditt djurs data” för att föra in resultat från mätningar men också
besvara frågor samt fliken ”Dialog” för att kontakta vårdgivaren om de har några frågor gällande systemet eller sitt djurs
hälsa. Här finns även ett hjälpavsnitt där djurägarna i text och bilder instrueras hur de på enklaste sätt utför mätningarna
hemma. Fliken ”Dialog” kan även nyttjas av vårdgivaren för att kontakta djurägaren om systemet indikerar en försämring av
djurets hälsa. Inlagd data skickas över internet till en databas där den lagras. Väl lagrad kan vårdpersonal och även djurägare
när som helst genom att logga in på webbportalen få tillgång till informationen. I studien ingick totalt 26 patienter, varav 17
hjärtsjuka och 9 friska individer . Samtliga djurägare hade deklarerat att de ville delta i studien och mottagit information om
dess utformning.
Bild 1. Exempelbild av grafer över valda fysiologiska parametrar. Andnings- och hjärtfrekvens är uppmätt och visas per 20
sekunder. Genom att markera en viss punkt på grafen erhålls inrapporterade värden aktuell dag i rutan till höger i bilden
3. Resultat och diskussion
PetHearts höga acceptans och användande bland djurägarna i studien i kombination med möjligheterna till bättre
hälsoövervakning och kommunikation indikerar att det skulle kunna vara ett bra komplement vid vård av hjärtsjuka hundar
och katter.PetHeart bidrar till att en hälsoförsämring hos hjärtsjuka katter och hundar kan upptäckas i ett tidigare skede, vilket
bidrar till en ökad livskvalitet, bl.a. genom att behov av att initiera eller justera medicinering kan upptäckas tidigt.
Andningsfrekvensen är den bästa enskilda parametern för att upptäcka hjärtsvikt. PetHeart skapade en ökad trygghet bland
djurägare till hjärtsjuka hundar och katter.
En synnerligen intressant användning av systemet var att djurägare fick rapportera sitt djurs data dagligen vid ändring av
hjärtmedicinering för att kunna kontrollera effekt på hälsotillståndet på distans. Speciellt användbart är detta vid utsättning av
en medicinering som bedöms att sannolikt vara onödig eller insatt på felaktiga grunder. Med hjälp av det beskrivna systemet
kan man lättare, även i poliklinisk verksamhet, våga sätta ut pågående medicineringar. Detta då en god kontroll av responsen
kan erhållas på distans. Ett ”Care at Distance” system, som det ovan beskrivna, kan ge ökat kurage hos veterinärer och
läkare att våga sätta ut medicineringar som ej gör någon nytta men kanske försämrar patientens hälsotillstånd och
livslängd. Det beskrivna systemet skulle kunna göra stor samhällsnytta om det utvecklades och kom till utbredd
användning.
References
[1] Gund, A. (2011) On the Design and Evaluation of an eHealth System for Management of Patients in Out-of-Hospital
Care. Diss. Göteborg: Chalmers Tekniska Högskola.
[2] Gund, A. (2008) Design of an Internet-Based Disease Management System for Chronic Heart Failure. Akad.lic. avh.
Göteborg: Chalmers Tekniska Högskola
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Sammanfattningar
Diagnos och behandling
Session 4B
Moderator:
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4B1
CEREBRAL BIOIMPEDANCE SPECTROSCOPY: STEPS TOWARDS STROKE DETECTION
1
Seyed Reza Atefi1, Fernando Seoane1,2, Kaj Lindecrantz1,3
KTH Royal Institute of Technology ,Huddinge , Sweden, 2University of Borås, Borås, Sweden. 3 Karolinska institutet, Stockholm, Sweden3
1. Introduction
Following cancer and cardio-vascular disease stroke is considered as the third cause of death world-wide [1]. Considering the
limitations of the most widely used diagnostic technologies for stroke detection, in particular imaging modalities, the need for
portable non-invasive and less expensive diagnosis technologies that will fill the gap between current clinical routines and
patient needs leading to faster and better treatment outcome is crucial. Earlier studies have demonstrated that electrical
bioimpedance spectroscopy (EBIs) measurements from the cerebral tissue contain useful clinical information related to
changes imposed to the cerebral tissue after the onset of the stroke [2] making EBIS a suitable candidate for this purpose.
2. Method
720 EBI measurements were collected from two different volumes ( Mc Central and larger, ML lateral and smaller) of 18
hemispheres of 9 subjects, three of whom suffering from unilateral stroke. These measurements were fitted into the Cole
function consisting of four parameters R0, resistance at DC, R∞, resistance at frequency infinity, α and fc i.e. the
characteristic frequency.. Based on Cole parameters, structural and intrinsic frequency dependent properties of the cerebral
tissue reported to be altered after the onset of stroke a number of features are extracted [3], see table 1. Later on these features
are fed into a tree classifier to evaluate the possibility of stroke detection based on these features.
Feature1
Table 1 Features
Feature2
Feature 3
(
(
⁄
⁄
)
)
3. Results
Final results with high degree of accuracy shows that after three hierarchical classification steps using the tree classifier a full
classification of healthy and damaged cerebral tissue is achieved.
Feature 2
Feature 3
Feature 1
Figure 1 Classification tree, at each node a threshold based on the features is applied and results are in leaves of the tree
4. Conclusion
Using three features originated from the spectral information and geometry dependency of electrical bioimpedance data
based on Cole parameters and a simple classification tree, an accurate classification between healthy brain hemispheres and
stroke damaged ones has been performed. Despite the small size of the database available these results are sufficient to show
that bioimpedance spectroscopy contains useful information to asses on stroke brain damage.
References
[1] G. A. Donnan, M. Fisher, M. Macleod, and S. M. Davis, "Stroke," Lancet, vol. 371, pp. 1612-23, May 10 2008.
[2] G. Bonmassar, S. Iwaki, G. Goldmakher, L. M. Angelone, J. W. Belliveau, and M. H. Lev, "On the Measurement of
Electrical Impedance Spectroscopy (EIS) of the Human Head," Int J Bioelectromagn, vol. 12, pp. 32-46, Jan 1 2010.
[3] S. R. Atefi, F. Seoane, and K. Lindecrantz, "Electrical Bioimpedance cerebral monitoring. Preliminary results from
measurements on stroke patients," in Engineering in Medicine and Biology Society (EMBC), 2012 Annual International
Conference of the IEEE, 2012, pp. 126-129
11
4B2
TOWARDS AMBULANCE BASED STROKE DIAGNOSTICS
Mikael Persson1,4, Andreas Fhager1,4, Hana Dobsicek Tréfna1,4, Yinan Yu1, Tomas
McKelvey1, Göran Pegenius2, Jan-Erik Karlsson3, Mikael Elam2,3,4
1
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3
4
Signal Processing and Biomedical Engineering, Dept. of Signals and Systems, Chalmers University of Technology, Göteborg, Sweden
Inst of Neuroscience and Physiology, Dept. of Clinical Neurophysiology, Sahlgrenska Academy, Göteborg University, Sweden
Neuro-division, Sahlgrenska University Hospital, Göteborg, Sweden
MedTech West, Göteborg, Sweden
1. Introduktion
Around 15 million people suffer a stroke each year. The global cost of stroke is hard to assess but the total European cost has
been estimated to 64.1 billion € per year. The human cost of stroke is horrific with 5 million deaths/year and another 5
million are permanently disabled. Most stroke patients are not receiving optimal treatment. The majority of these are
Ischemic stroke patients and should ideally receive acute thrombolytic treatment, dramatically reducing or abolishing
symptoms. Today, less than 5% of these patients reach diagnosis and treatment in time, mainly due to long lead times in
transport to and from the diagnostic instruments. Such treatment must be initiated within 4.5h after stroke onset, preceded by
safe differentiation of haemorrhagic vs. ischemic stroke since thrombolysis can severely aggravate a haemorrhagic condition.
Today this requires brain scans, calling for hospitalization before treatment. In a close collaboration between biomedical
engineering, signal processing and medical scientists we have developed a system for screening patients for the presence,
location and size of an intracranial haemorrhage with the ambition to create a device that could be used upon arrival in the
emergency room, or by ambulance personnel at the scene of incident.
2. Methods
The technology developed is a result of a long-term
project dealing with microwave propagation in human
tissues. The simplicity and size of a microwave-based
diagnostic system underlined the possibility of creating
an ambulance-based pre-hospital diagnostic system for
stroke patients. The system, shown in the picture to the
right, further has the advantage of being completely safe
and without side effects since the power levels used are
only a fraction of what is transmitted by a mobile phone.
The stroke detection system consisted of antennas
sending and receiving microwave signals, mounted on a
helmet-like supporting structure. In order to provide a
comfortable fit of the system, patch antennas with a flat
surface facing the skull were used.
These antennas had a rectangular shape with the radiating metallic structure of the antennas in the form of isosceles triangle
with a height of 37 mm and a width of 25 mm, printed on the surface facing the skull. A total of 12 antennas were used and
distributed uniformly over the surface of the skull to ensure good coverage of the brain. To accommodate varying skull sizes
shapes of the patients, containers of soft plastic were placed between skull and antennas and filled with water to fill the gap.
The use of the plastic containers ensured a good electromagnetic coupling between the antennas and the skull. In the
measurement procedure each antenna is consecutively used as a transmitter, with all remaining antennas in receive mode. In
total 66 independent transmit-receive channels were measured over a large band of frequencies, 0.3-3.0 GHz. The
classification algorithm is derived by using a labelled set of training data with purpose of delivering estimates of specific
subspaces for each of the two classes. The estimated subspaces are the reduced by removing a number of dimensions for each
subspace in order to increase the smallest principal angle between the subspaces. The classification algorithm projects the
measurement data vector onto both the subspaces and selects the predicted class label based on which of the projections
results in the longest vector. The accuracy of the classifier is evaluated on the clinical data by combining the leave-one-out
cross validation method with a bootstrap sampling technique to reduce the variance of the performance estimates.
3. Results
We have performed a clinical study using the above described brain diagnostic devices based on microwave technology.
With the detector aimed at identifying all 10 patients with haemorrhagic stroke, 13 out of 15 ischemic stroke patients were
clearly separated from haemorrhagic stroke patients whereas 2 were not. The results show that this type of device and the
associated algorithms can differentiate haemorrhagic from ischemic stroke patients.
In summary we have reported on a new system and a clinical studies that set the stage for pre-hospital diagnosis and
treatment in ambulances for the 15 million yearly stroke patients around the world thus helping society to meat one of the
major unmet challenges of the global health care system.
12
12
4B3
ASSESSING OBSTRUCTIVE AIRWAY DISORDERS BY MEANS OF COMPUTATIONAL FLUID
DYNAMICS (CFD)

Mihai Mihăescu1, Laszlo Fuchs1, Nelson Powell2

1.Background and Motivation
The upper respiratory tract is susceptible to obstructionlike abnormalities that can be caused by various mechanisms at one
or multiple locations and can affect the airway functions. Often, the interaction between the flow and the obstruction involves
dynamic changes in the flow regime, flow recirculation regions, flowinduced instabilities, nonlinear pressuredrop/flow rate
relations, selfexcited oscillations of the soft tissue, and flowinduced noise. It is believed that the changes in the flow
patterns associated with an obstruction are playing an important role for the progress of the disorder over the time.
Obstructive Sleep Apnea (OSA) is the most common obstructive airway disorder, affecting more than 12 million people in
US alone. It is characterized by partial or complete narrowing of the pharyngeal airway during sleep (hypopneas and apneas),
resulting in partial or complete airflow cessation and Oxygen desaturation. Overnight Polysomnography is considered the
goldstandard for its diagnosis. It is an expensive and time consuming process for both patient and evaluator. The OSA
severity is expressed using ApneaHypopnea Index (AHI), which represents the total number of hypopneas and apneas
occurring in one hour of sleep. A mild OSA is indicated by an AHI between 5 and 15, while severe conditions are those for
which AHI is greater than 30. Medical imaging techniques (e.g. Computed Tomography, Magnetic Resonance Imaging)
facilitated anatomical measurement of the airway, but they have little clinical utility for quantifying the functional impact of
an airway obstruction. These techniques cannot offer details about the effect of the airway’s anatomical features on the
airflow or on airway resistance to assess obstruction’s severity.
2.Methodology
An upper respiratory tract simulator based on medical imaging for extracting patientspecific upper respiratory tract anatomy
and Computational Fluid Dynamics (CFD) for computing the airflow through the pharyngeal airway are employed [1]. CFD
is able to predict fluid flow characteristics by solving the physical laws of fluid mechanics (NavierStokes equations) using
numerical methods and algorithms embodied in the form of a computer code. The tool is proposed as a nonintrusive and
inexpensive diagnosis technique for obstructive airway disorders. Thus, not only the specific anatomic measurements are
acquired (i.e. pharyngeal airway dimensions, crosssectional area, and volume) but also pertinent data to the airflow are
computed (e.g. airway resistance, flow patterns, velocity, pressure, turbulence production, or wall shearstresses). The data
obtained in normal healthy pharyngeal respiratory tracts (Controls) are averaged and used to generate a “Baseline” against
which the results obtained in sleepdisordered breathing patients at pre and posttreatment are compared and contrasted.
3.Results
Clinical and CFD based data concerning four healthy adult subjects
and four OSA patients at pre and posttreatment conditions are
presented in the Figure 1. The medical imaging and the AHI data
were obtained at the Sleep and Research Center, Stanford
University. Despite of the low number of subjects considered, a
strong correlation is observed between the CFD data (mean
pharyngeal airway resistance) and the clinically obtained AHI
values. A correlation coefficient of  was calculated. About
an order of magnitude difference between the pre (red) and the
posttreatment resistances (green) is found. The posttreatment
airway resistances are bellow or in the range of the averaged airway
resistance estimated for the healthy subjects (blue). The proposed
approach allows thus differentiating between healthy subjects and
individuals with OSA.
Figure 1: Predicted airway resistance and clinically
measured AHI plotted for four Controls and four
OSA patients at pre and posttreatment conditions.
4.Discussion
The present study represents an important step in building a tool for quantifying OSA and for assessing treatment outcome.
Such a computational model shall enable to determine and understand the pathophysiology of the sleep disorder and the
risks for airway collapse and flow induced obstruction at pre and posttreatment conditions. The simulation of the
pharyngeal airflow may allow the surgeon to add quantitative data into his/her decision making, which is often based on
semiquantitative or qualitative clinical findings.
Acknowledgments
The work is supported by the Swedish Research Council (VR 62120124256). Also, the financial support from the Göran
Gustafsson Stiftelse by means of “The Göran Gustafsson Young Scientist Award (UU/KTH)” conferred to Dr. Mihaescu is
greatly acknowledged.
References
[1] M. Mihăescu, G. Mylavarapu, E. Gutmark, and N. Powell, Large Eddy Simulation of the pharyngeal airflow associated
with Obstructive Sleep Apnea Syndrome at pre and postsurgical treatment. , 44, 22212228, (2011).
13
4B4
DEVELOPING A WEARABLE MICROWAVE INSTRUMENT FOR DETECTING THORAX
INJURIES—TESTS ON A PNEUMOTHORAX PHANTOM
1–3
1
1
1, 2
1, 2
1, 2
Stefan Candefjord , Prateek Saraswat , Robert Samo , Tomas McKelvey , Andreas Fhager , Mikael Persson
Chalmers tekniska högskola, Göteborg, Sweden 2MedTech West, Göteborg, Sweden 3SAFER Vehicle and Traffic Safety Centre at Chalmers
1
1. Introduction
Traumatic injuries is the leading cause of death for young people. A quarter of these deaths are a consequence of thorax
injuries [1]. Pneumothorax (PTX) is a collection of air in the thoracic cavity caused by a rupture in the membranes
surrounding the lung. Failure to diagnose and swiftly treat a PTX that is enlarging may cause patient death [1]. There is a
need for an instrument to be used in the prehospital setting for objective detection of PTX.
2. Materials and Methods
A wearable microwave instrument with six antennas was constructed using a leather belt and in-house fabricated patch
antennas; measurements were performed on healthy volunteers (Figure 1). A simplified model of the human thorax was
constructed using plastic containers of suitable sizes, filled with an appropriate mixture of ethanol and deionized water to
obtain realistic dielectric properties; a container in the shape of an elliptical frustum (inner volume 12 L, with the smaller
ellipse as the base) represented the thoracic cavity, and two cylindrical containers (inner volume 2 L) formed the lung space
(Figure 1). To simulate a PTX, the lung space was left empty and a plastic bag resembling a collapsed lung filled with a
dielectrically suitable liquid was placed inside. Measurements were performed for PTX sizes of 10%, 20% and 50% in the
left or the right lung; sixty measurements were randomly drawn from this dataset and represented the PTX observations. An
additional sixty measurements were performed on a phantom without PTX. The belt was repositioned after every third
measurement. Measurements were conducted in a random order. A classification algorithm based on finding the minimum
distance to the subspace bases, which were calculated by singular value decomposition of the training data matrix, was used
to distinguish between the measurements of No PTX and PTX. The leave-one-out approach was used, i.e. the sample to be
classified was not included in the training data matrix, in order to not overestimate the classification performance.
3. Results & Discussion
Measurements of the human thorax and the thorax model showed similar characteristics. The classification algorithm
differentiated PTX and No PTX (Figure 2). All No PTX and all except two PTX observations were correctly classified. This
is an encouraging result for pursuing the development of an instrument for PTX detection in the prehospital setting.
References
[1] A. Sharma and P. Jindal, Journal of Emergencies, Trauma, and Shock, 71, 34–41 (2008).
Figure 1: Left: The wearable microwave device (earlier version with four antennas). Right: Top view of the human thorax
model, antenna locations are labelled A1–A6.
PTX
Subspace distance [−]
Subspace distance [−]
No PTX
2
1
0
d
No PTX
d
PTX
3
2
1
0
d
No PTX
d
PTX
Figure 2: Box plots showing the distance to each subspace basis for the two classes, i.e. No PTX or PTX. The line in the
middle of the box shows the median, and the bottom and the top of the box show the 25th and 75th percentile, respectively.
14
14
4B5
A compact wideband antenna for microwave hyperthermia system
1
Pegah Takook1, Hana Dobsicek Trefna2, Mikael Persson3
Chalmers university of technology, Göteborg, Sweden. 2 Chalmers university of technology, Göteborg, Sweden.
3
Chalmers university of technology, Göteborg, Sweden
1. Introduction
Hyperthermia treatment is a medical treatment during which the temperature is raised in tumours for a sufficient period of
time, to kill the cancer cells or make them more sensitive to ionizing radiation or chemotherapy.
Different type of antennas have been used so far in deep hyperthermia applicators, such as water-filled waveguide antennas,
dipole antennas or probe-fed patch antennas. These antennas are either large and heavy (like as the waveguide antennas) or
present very narrow bandwidth which are not desired characteristics.
In this paper we present a compact, wideband antenna to be used in hyperthermia antenna applicator. This applicator is
developed for microwave hyperthermia of deep seated tumours in head and neck.
The antenna should be of small size, with wide frequency band and directive radiation pattern. The desired wide bandwidth
of 0.4 to 0.9 GHz, is due to multiple frequency approach in our treatment strategy.
2. Method
The antenna consists of two parts: the self-grounded Bow-tie antenna and the balun. The Bow-tie antenna covered, by teflon
from the upper-side, is completely immersed in water. The Teflon improves the antenna's reflection coefficients and high
permittivity of the water leads to a significantly reduced size antenna.
To transform the 30-ohm-impedance feed-line of Bow-tie in the background of water to a 50-ohm-impedance microstrip line,
a wideband balun has been designed.
Finally the shape and size of the water bolus is quantified by 50% iso-SAR contours as indicators of penetration depth and
the directivity.
3. Results
Our designed wideband balun presents a return loss of better than 10 dB and the transmission coefficient about -0.5 dB over a
bandwidth from 0-1 GHz.
Also the simulations results of the antenna shows the best performance in terms of the S11 for the bow-tie of size 18*27*7
mm3 and conical shape water bolus of size 40*80*30 mm3 (diameters of the upper and lower circular bases and height). The
obtained reflection coefficients are below -10 dB over most of the desired bandwidth, and below -5 dB for less than 0.45 GHz
and higher than 0.85 GHz.
Figure 1: Simulated bow-tie antenna in water bolus with the designed balun
4. Discussion and conclusion
The presented self-grounded bow-tie antenna with added teflon, immersed in water-filled conical shape bolus and with the
designed wideband balun, presents a wideband performance over the desired frequency range of 0.4-0.9 GHz.
References
[1] H.D. Trefna, J.F. Bakker, J. Vrba, Mikael. Persson. ''Evaluation of a patch antenna applicator for time reversal
hyperthermia.''International Journal of Hyperthermia, March 2012 .
[2] M.M. Paulides, J.F. Bakker, N. Chavannes, G.C. Van Rhoon. ''A patch antenna designed for application in a phased-array
head and neck hyperthermia applicator.'' IEEE Trans. Biom. Eng.
15
4B6
APPLICATOR FÖR MIKROVÅGSBASERAD BEHANDLING AV HUVUD- OCH HALSTUMÖRER
1
1
2
Hana Dobšíěek Trefná , Pegah Takook , Johanna Gellermann , Mikael Persson
1
2
Chalmers University of Technology, Sweden. University Hospital Tubingen
1
1. Introduction
Hyperthermia is presently used as an adjuvant to the radiation therapy in the treatment of certain types of cancers. Recently,
randomised trials have shown a significant advantage of combining hyperthermia with radiotherapy and/or chemotherapy in
the treatment of solid tumours [1,2]. The objective of hyperthermia treatment is to raise the temperature in the tumour to a
therapeutic level 41 – 44 C for a sufficient period of time to achieve cell death or render the cells more sensitive to ionizing
radiation and chemical toxins. In this contribution, we present a novel design of an antenna applicator for hyperthermia
treatment in Head & Neck region.
2. Method
The applicator consists of 12 to 18 elements arranged in one to three ring set-ups. The distance between the rings is 30 mm.
The self-grounded Bow-Tie immersed in conical water bolus serves as an applicator element,. The operating frequency range
is from 400 to 1000 MHz. In order to keep distance in terms of wavelength between radiating elements body at different
frequencies, the diameter of the applicator is adjustable and varies between 340 and 460 mm. In order to cool down the body
surface, an additional water layer is placed between the body and water boli of the antennas. This layer has thickness of 1-2
cm and contain circulating cold water.
3. Results
The focusing abilities of the applicator are evaluated by using a numerical model of an anthropomorgical phantom of H&N
region. The phantom, containing small laryngeal tumor of volume approx. 15 mm 3 consists of 6 tissues. The treatment plans
were calculated by using the time reversal algorithm [3].
The results show a considerable heating in terms of SAR in the target region with a remarkably low heating in critical tissues
(i.e. spinal column). The obtained SAR distribution is favorable, although a relatively high level of energy is also absorbed
on the surface of the body. It is apparent that this heating is local and not expected to cause problems as it can be cooled by
blood perfusion and water bolus. The obtained results also justify advantages of using the multi-frequency approach in
treatment planning.
4. Conclusions
The results presented in this study are promising, awaiting the experimental evaluation on the physical version of the
phantom.
References
[1] J. Van der Zee, D. Gonzáles Gonzáles, et al.,” Comparison of radiotherapy alone with radiotherapy plus hyperthermia in
locally advanced pelvic tumours: a prospective, randomised, multicentre trial”, Lancet, vol. 355, pp. 1119-1125, 2000.
[2] R.D. Issels, L.H. Lindner, J. Verweil , et al.,”Neo-adjuvant chemotherapy alone or with regional hyperthermia for
localised high-risk softtissue sarcoma: a randomised phase 3 multicentre study.”, Lancet Oncol., Vol.11(6), pp. 561-70, 2010.
[3] H. Dobšíček Trefná, J. Vrba, and M. Persson, ”Time-Reversal Focusing in Microwave Hyperthermia for Deep-Seated
Tumours”, Phys Med Biol, vol 55, pp. 2167-85, 2010.
Figure 1: Applicator design and SAR distribution in phantom containing laryngeal tumor.
16
16
Sammanfattningar
Ehälsa/IKT II
Session 2C
Moderator: Bengt Arne Sjöqvist
17
17
2C1
itACiH - it-stöd för Avancerad Cancervård i Hemmet
1
1
2
3
4
Jimmy Johansson , Boris Magnusson , Rickard Fredin , Hlin Thorgeirsson
2
Medicinsk teknik, Skånes universitetssjukhus, Lund/Malmö, Sweden. Datavetenskap, Lunds Tekniska Högskola, Lund, Sweden.
3,4
Palliativa enheten, Primärvården Skåne, Lund, Sweden.
Inledning
Ett integrerat it-stöd för avancerad cancervård i hemmet är nu i klinisk drift inom den palliativa enheten i Lund. Den mobila
vårdpersonalen har en mobil enhet med uppdaterad information för respektive patient de ska besöka samt stöd för
dokumentering. Den mobila enheten utbyter kontinuerligt information med en avdelningsenhet som är placerad på
verksamhetens expedition. På så sätt kan den rondande vårdpersonalen få en uppdaterad bild av patienternas status.
Den mer avancerade medicintekniska utrustningen i form av provtagningsutrustning, infusionspumpar och
monitoreringsutrustning är också uppkopplad mot systemet och tekniken utvärderas i en simulerad hemmiljö, tillsammans
med patienter inom den palliativa slutenvårdavdelningen. På så sätt kan vi ta med oss feedback i vidareutvecklingen och
bemöta de krav som ställs för att på ett säkert sätt integrera denna typ av utrustning i hemmet. Vi lägger stor vikt vid
användbarhet och har experter i projektet som fortlöpande utvärderar detta.
Bakgrund
Projektet, it-stöd för Avancerad Cancervård i Hemmet (itACiH), syftar till att upprätta en avancerad vårdplats i hemmiljö
med inriktning mot cancervård. Antalet cancerfall beräknas öka, även oberoende av den ökande andelen äldre i befolkningen.
En av tre svenskar drabbas av cancer och med allt bättre möjligheter till behandling lever allt fler längre med sin sjukdom
vilket innebär ökade krav på avancerad sjukvård i livets slutskede. För att det ska vara möjligt att ge kvalitativ vård med den
ökande belastningen på samhället som detta innebär måste det finnas nya vägar för omvårdnad både under aktiv behandling
och i livets slutskede. Ny teknik kommer att öka antalet patienter som kan ges möjlighet att vårdas hemma, vilket en stor del
av dagens patienter önskar.
Det huvudsakliga målet för projektet är att göra det möjligt för fler patienter med cancer att vårdas hemma. Detta förutsätter
att det kännas lika tryggt att vara hemma som på en vårdavdelning. Genom att utveckla tekniker för övervakning av
utrustning som finns runt patienten, i vissa fall fjärrstyrning av utrustningen, kombinerat med kommunikation mellan hem
och vårdpersonal, såväl vårdavdelning som mobila vårdteam, hoppas vi kunna åstadkomma en sådan situation.
Projektet finansieras genom VINNOVA:s program för utmaningsdriven innovation som riktar sig till breda sektors- och
ämnesöverskridande konstellationer som gemensamt vill arbeta för att möta samhällets utmaningar. Konstellationen består av
företag från olika sektorer, tvärdisciplinär forskning från universitet, forskningsinstitut, offentlig sektor och ideella
organisationer enligt bilden nedan.
Projektet, itACiH, har en budget på 22 miljoner, varav 10 miljoner från VINNOVA och 12 miljoner i form av
medfinansiering från partners, och en tidsplan som sträcker sig över 2012 och 2013.
Utveckling
I detta tvärvetenskapliga projekt samverkar datatekniker, medicintekniker, sjukvårdspersonal och företag från olika
discipliner för att tillsammans lösa detta komplexa problem. Projektet drivs efter en iterativ modell där två delprojekt,
utveckling och kravställning, fortgår parallellt. Processer för utveckling, riskhantering och användbarhet etablerats för att
hantera de regulatoriska kraven för medicintekniska produkter.
Fram till nu har fokus legat på att etablera en underliggande infrastuktur samt tillhandahålla ett integrerat it-stöd för
vårdpersonalen. Nästa steg blir att även integrera enheter som stödjer patienter och anhöriga. Vi har genom samarbetet med
Nätverket mot cancer genomfört workshops tillsammans med patienter och anhöriga för att designa ett system som utgår från
de viktigaste behoven och för att ta hänsyn till de integritetsaspekterna man tidigt stöter på.
Det pågår ett antal examensarbete inom ramen för projektet som syftar till att anpassa produkter som idag är avsedda för
sjukhusbaserad vård och behöver anpassas vad gällande både säkerhet och mobilitet.
Resultat och slutsatser
Ungefär 1,5 år in i projektet ser vi att det som tas fram både är välkommet i verksamheten och med stor sannolikhet är ett
måste för att avancerad sjukvård i hemmet ska kunna växa i den omfattningen som prognoserna pekar på. Utöver behovet, av
ett integrerat it-stöd, som identifierats inom verksamheten för avancerad sjukvård i hemmet har ett tydligt behov identifierats
i andra ambulerande verksamheter som t.ex. primärvården och kommunen. Även andra verksamheter inom sjukhusbaserad
specialiserad öppenvård såsom diabetesmottagningen, hemdialysenheten och barnkliniken har visat stort intresse.
Nu arbetar vi för att i första hand slutföra utvecklingen som möter den avancerade cancervården i hemmet men tittar även på
möjligheten att specialanpassa systemet för barn och andra vårdområden.
18
2C2
A Novel Data-Mining Approach Using Social Media to Respond to Outcomes of Diabetes Treatment
1
1
2
3
ALTUG R. AKAY , ANDREI DRAGOMIR BJÖRN-ERIK ERLANDSSON
2
3
KTH Royal Institute of Technology, Huddinge, Sweden. University of Houston, Houston, Texas KTH Royal Institute of Technology,
Huddinge Sweden.
1. Heading (eg Introduction)
Social media, ranging from personal messaging to live foras, is providing limitless opportunities for patients to discuss their
experiences with drugs and devices. It is also providing limitless opportunities for companies to receive feedback on their
products and services [1]. Pharmaceutical companies are already looking at social network monitoring as a top priority within
their IT departments, potentially creating an opportunity for rapid dissemination and feedback of products and services to
optimize and enhance delivery, and reduce costs [2].
Traditional social sciences use surveys and involve subjects in the data collection process. Limited by this process, data
collected is of small sizes and typically hundreds of subjects in one study. By contrast, thousands of users of social media
produce inordinate amounts of data with rich user interactions. There are two simple ways to extract this information: 1)
crawling using site provided APIs, or 2) scraping needed information from rendered html pages. Many social media sites
provide APIs: Twitter, Facebook, YouTube, Flickr, etc. We can also follow how its properties change over time, which
would greatly interest public health studies.
2. Heading (eg Method)
We used text and data-mining tools in Rapidminer (www.rapidminer.com) to develop opinion labels about each drug and
device (positive, negative, neutral) per node within a network, build networks from the search results of the forum, and
developed a network ranking system reflecting the degree to which the respective network is involved in the opinion
formation about the drug/disease.
Each forum group (separated by drugs and/or devices discussed) was fed into Rapidminer and preprocessed by removing
unwanted characters (HTML tags, punctuation, numbers) and common stop words (e.g. a, the, it, etc.), breaking down words
into token words, stem tokens into ‘root words’ (e.g. working ->work; lost, lose->los). The end result was a wordlist per
vector using a binary system to identify words within a vector (‘1’ = the word was present, ‘0’ = the word was absent).
3. Results
The following figure is the graphical representation of the SOM of the positive words group. We used a 10 x 10 map size
with thirty variables present.
Fig. 1. Positive Words
The clustering resulting from the SOM analysis reveal that the positive words (along with positive words and drugs) have a
larger presence in the cluster groups. Negative words (along with negative words and drugs) had a much lower presence in
the cluster groups. We developed a list of words dominating the clusters.
4. Discussion
The goal of this study was to transform forum posts into vectors to scan for patterns in the responses to gauge
consumer opinion of the drugs and devices used to treat diabetes mellitus. The clusters belonging to the
‘Positive’ and ‘Positive + Drugs’ categories contained more positive words (per vector and per frequency)
compared to the ‘Negative’ and ‘Negative + Drugs’ group. This gives the impression of an overall positive user
satisfaction and experience with the specified drugs and devices.
A future study will go more deeply into the interaction amongst the users to develop a more thorough web of
user influence and opinion and how user influence (based on quality of posts and ranking within the forum)
affects interactions with other users (replies, friendships, the timing and quality of posts in threads) [3]. Future
research will expand to include other diseases such as oncology. With social media becoming an expanding
venue for people to express their thoughts, ideas, and reactions, it represents a goal mine for companies seeking
to optimize health delivery and reduce costs.
References
[1]
[2]
[3]
Alberto Ochoa, Arturo Hernández, Laura Cruz, Julio Ponce, Fernando Montes, Liang Li and Lenka Janacek (2010). Artificial Societies
and Social Simulation Using Ant Colony, Particle Swarm Optimization and Cultural Algorithms, New Achievements in Evolutionary
Computation, Peter Korosec (Ed.), ISBN: 978-953-307-053-7, InTech (http://www.intechopen.com/articles/show/title/artificialsocieties-and-social-simulation-using-ant-colony-particle-swarm-optimization-and-cultural)
“Pharma 2.0 – Social Media and Pharmaceutical Sales and Marketing”
Identifying influential users in an online healthcare social network, X. Tang, C.C Yang, ISI 2010
19
2C3
Case Based Reasoning in Support of the LVAD Surgical Treatment
Ankica Babic, PhD, Department of Biomedical Engineering, Linköping University
Introduction. In approximately 1-3% of patients undergoing open-heart surgery, there is a need for
Left Ventricular Assist Device (LVAD) due to heart failure when weaning from cardiopulmonary
bypass (CPB) [1]. To minimize the high mortality and morbidity rates it is important to chose the right
treatment for the particular patient situation. The amount of the data collected in electronic patient
records might be limited for an elaborate statistical analysis, but it is very critical for assuring a timely
and accurate clinical insight into a patient particular situation. Case Based Reasoning (CBR)
methodology provides means of collecting patients cases and retrieving them following the clinical
criteria [2]. By studying previously treated patients with similar backgrounds, the physician can get a
better support for deciding on treatment and be better prepared for complications that might occur
during and after surgery.
Case Based Reasoning (CBR) engine was developed using an extended version of the Nearest
Neighbor'a algorithm, which uses logarithms that emphasize small differences between similar cases.
A patient case (Figure 1) is represented as a combination of perioperative variable values and
operation reports. Physicians could review a selected number of cases by browsing through the
electronic patient records and operational narratives which provides an exhaustive insight into the
previously treated cases.
Figure 1. A Patient Case.
Results. An evaluation of the search algorithm suggests good functionality: an experienced physician
retrieves cases using fewer clinical variables while the novice selects more variables which influences
the distance calculation and consequently the set of the K nearest cases. The CBR engine had been
implemented as a part of a web-based decision support system for thoracic surgery.
Literature. 1. B Peterzén, U Lönn, A Babic, H Granfeldt, H Casimir-Ahn, H Rutberg. Postoperative Management of
Patients With Hemopump Support After Coronary Artery Bypass Grafting. Ann. Thorac. Surg. 1996;62: 495-500
2. Holt A et al., The Knowledge Engineering Review / Volume 20 / Issue 03 / September 2005, pp 289-292
20
2C4
UTVECKLING AV BESLUTSSTÖD FÖR HJÄRTPUMPSINSTÄLLNING
1
2
3
4
5
6
7
Lisa Nilsson , Boris Magnusson , Lars Algotsson , Jimmy Johansson , Matilda Landgren , Anders Heyden , Ida Rasmark , Erik
8
Lindsten
1
Projektledare, Skånes universitetssjukhus, Medicinsk Teknik, Lund, Sverige.
2
Professor, Lunds Tekniska Högskola, Institutionen för datavetenskap, Lund, Sverige
3
Överläkare, biträdande klinikchef, Skånes Universitetssjukhus, Kliniken för Thoraxkirurgi, Anestesi och Intensivvård, Lund, Sverige
4
Ansvarig för Forskning och Utveckling, Skånes universitetssjukhus, Medicinsk Teknik, Lund, Sverige
5
Doktorand, Lunds Tekniska Högskola, Matematikcentrum, Lund, Sverige
6
Professor, Lunds Tekniska Högskola, Matematikcentrum, Lund, Sverige
7
Examensarbetare, Lunds Tekniska Högskola, Institutionen för datavetenskap, Lund, Sverige
8
Examensarbetare, Lunds Tekniska Högskola, Institutionen för datavetenskap, Lund, Sverige
1. Introduktion
Hjärttransplantation är sista utvägen för patienter som lider av allvarlig hjärtsvikt. Antalet patienter som väntar på
hjärttransplantation är många fler än tillgången på donatorhjärtan. I väntan på ett nytt hjärta får vissa patienter en hjärtpump
inopererad för att avlasta det egna hjärtat. Hjärtpumpens hastighet är kontinuerlig, och behöver justeras många gånger innan
man har hittat en lämplig hastighet. För att ställa in hjärtpumpens hastighet inhämtar man information både från olika
uppmätta tryck, såsom centralt venöst blodtryck och kapillärt inkilningstryck i lungkretsloppet, samt ultraljudsbilder av
hjärtat. Att bara utgå från de tryck man mäter är vanskligt då dessa tryck ökar både då pumpen går för fort och för långsamt.
Med hjälp av ultraljudsbilder av de fyra kamrarna i hjärtan är det möjligt att avgöra om pumpens hastighet är för hög eller för
låg. En ideal hastighet resulterar i att vänster hjärtkammares storlek inte är abnormal och att kammarskiljeväggen inte är
förskjuten för mycket åt något håll. Dock kan ett fyrkammarultraljud vara svårt att tolka då vinkeln mellan
ultraljudsapparaten och hjärtan kan variera beroende på hur den appliceras, men också på grund av patienternas variation i
form och storlek, eller hjärtats placering i kroppen.
2. Bakgrund
Forskningsprojektet syftar till att hitta nya metoder för optimering av hastighet för en inopererad hjärtpump. Projektet drivs
genom ett samarbete mellan Thoraxintensiven och Medicinsk Teknik vid Skånes Universitetssjukhus, samt institutionen för
datavetenskap, institutionen för reglerteknik och Matematikcentrum vid Lunds Tekniska Högskola.
3. Metod och resultat
Att ställa in hjärtpumpens hastighet optimalt är idag komplicerat, och trots de supportsystem man har idag råder fortfarande
osäkerhet om den hastighet man väljer är korrekt. Målet med projektet är att utveckla ett beslutsystem för att lättare kunna
avgöra om pumpens hastighet skall ökas eller minskas. Beslutsstödet skall kombinera insamlad information från
patientövervakningssystemet med information från ultraljudsbilder i realtid och analysera denna. Återkoppling skall kunna
ges i realtid till de närvarande läkarna och kunna ge en indikation på om pumpens varvtal bör ökas eller minskas.
Beslutsstödet skall utformas på sådant sätt att det är intuitivt att använda och har hög användbarhet för de läkare det är tänkt
att stödja.
Projektet består av två delar, dels analysen av ultraljudsbilderna, och dels av sammanställningen av ultraljudsbildernas
resultat med de fysiologiska parametrarna som utläses från patientövervakningen och analysen och presentationen av denna
samlade data. I projektet ingår att identifiera vilka parametrar i ultraljudsbilden som är vitala, såsom kammarskiljeväggens
rörlighet och kamrarnas storlek, och att i analysen översätta detta till en, eller flera, numeriska parametrar som går att
använda i en algoritm. Denna bildanalys görs med hjälp av variationsmetoder.
Projektet baserar sig i tidigare arbeten på Lunds Tekniska Högskola och Medicinsk teknik. Ett tidigare projekt har resulterat i
en databas där en patients alla mätvärden från patientmonitorn sparas och långtidslagras. Från denna databas hämtas de
övervakningsparametrar som används i analysen. Man använder sig också av PalCom för kommunikation mellan
beslutsstödsprogrammet, ultraljudsapparat och databas. PalCom är resultatet av ett EU-projekt som pågick 2004-2007 och
involverade flera länder och universitet, däribland Lunds Tekniska Högskola och institutionen för datavetenskap. PalCom
tillhandahåller ramverk för att skapa flexibla anslutningspunkter för enheter och applikationer. För att underlätta
integrationen ytterligare använder applikationerna formatet HL7 för kommunikation sinsemellan och mot externa system.
4. Diskussion
Projektet är avgränsat till att utveckla en prototyp som kan testas och utvärderas av sjukvårdspersonal på Thoraxintensiven. I
förlängningen kan man tänka sig att detta arbete kan leda till förfinade metoder att analysera de fysiologiska parametrar som
är av intresse för hjärtpumpsinställning. Prototypen skulle kunna användas till att utvärdera olika algoritmer för att stödja
hjärtpumpsinställning, och kanske i förlängningen att inte bara ge indikation om huruvida pumpens hastighet skall justeras
uppåt eller nedåt, utan också kunna ge förslag på hastighet.
21
Sammanfattningar
Medicinska bilder I
Session 3C
Moderator: Thomas Jansson
22
22
3C1
DETECTION OF IRON OXIDE NANOPRTICLES IN RAT LYMPH NODES USING
MAGNETOMOTIVE ULTRASOUND IMAGING
Maria Evertsson1, Magnus Cinthio1, Sarah Fredriksson2, Pontus Kjellman2, Rene in 't Zandt2, Fredrik Olsson2, Hans W. Persson1,
Tomas Jansson3
1
Electrical Measurements, Faculty of Engineering LTH at Lund University, Lund, Sweden. 2 Genovis AB, Lund, Sweden. 3 Clinical Sciences,
Lund University, Lund, Sweden
1. Introduction
Breast cancer and malignant melanoma spread mainly through the lymphatic system. If the cancer has spread it is most likely
to find metastases in the sentinel lymph node (SLN), the first lymph node draining the tumor. The SLN is by invasive surgery
removed and histologically examined. It is desirable to find new methods and tracers to localize SNLs to improve the
accuracy of the detection and removal of cancer infected lymph nodes. In this study we aim to detect multimodal
superparamagnetic iron oxide nanoparticles (SPIO-NP) in rat SLNs in situ, using the new imaging technique magnetomotive
ultrasound imaging (MMUS). In MMUS a time-varying external magnetic field acts to move the NPs and, thus, the NP-laden
tissue. This movement can be detected by proper processing of ultrasound data. Recently we developed a frequency and
phase gated algorithm which efficiently reduce motion artifacts. The algorithm has shown promising results in phantom
studies [1], but has not yet been verified in animals. If presence of adequate signal can be established in an animal model,
there is a potential for MMUS to be used as a bed-side surgical guide, imaging the very same particles that were used in prior
staging with other imaging techniques (e.g MRI and SPECT).
2. Method
Seven Wistar rats were injected with 100µL nanoparticle solution in one of their hind paws, four with 31nm NPs and three
with 67 nm NPs. Further, the injections were given as a low or a high concentration (0.3 and 3 mg iron oxide/mL
respectively). Only one animal received the high concentration 67nm NPs. 24 hours post injection the animals were
sacrificed and imaged with a high frequency ultrasound scanner (Visualsonics VEVO 2100). Each rat was positioned
between the transducer (center frequency 21 MHz) and a solenoid with a cone shaped iron core, imaging the lymph node in
the fold of the knee, proximal to the injection site. The solenoid was excited with various voltages (10, 20, 30Vpp) and
frequencies (5-15Hz, in steps of 2.5Hz). Displacements were calculated from acquired RF IQ-data. Signal to clutter ratios
were given as average displacement in the lymph node divided with that in the fat capsule surrounding the node.
3. Results and discussion
Fig. 1 shows: (a) a B-mode image of a rat lymph node after injection of 100µl 0.3mg/mL solution of 31nm NPs; (b) the total
magnetomotive displacement at 5Hz 30V coil excitation; (c) the phase distribution at the detected frequency and (d) the
frequency and phase-discriminative displacement. The displacement and phase magnitudes can be read from the color bars,
note the different scales. The displacement is in the same order as in previous phantom studies. The signal to clutter ratio in
the case depicted in Fig. 1 (d) was 16.7 dB compared to an average of 6.7dB for all measurements. The displacement tended
to decrease with increasing frequency, and to increase with increasingexcitation voltage. For example it was approximately
twice as large at 5Hz than 15Hz, and three times larger at 30V compared to 10V. There was also a tendency that smaller
particles induced a larger magnetomotive displacement. From the phase map 1(c) it can be seen that the magnetomotive
displacement of NP-laden tissue induces a counteracting motion with opposite phase in tissue surrounding the lymph node.
The phase discriminative algorithm however effectively suppresses this counteracting motion.
4. Conclussion
In breast cancer and malignant melanoma it is important to localize SLNs to investigate if the cancer has spread. We have
here established magnetic excitation parameters for successful MMUS imaging in a preclinical SLN model. Further, the
results show that MMUS has potential as a stand-alone modality for other imaging applications, besides from SLN, such as
stem cell tracking and cardiovascular research.
References
References
[1] M. Evertsson, M. Cinthio, S. Fredriksson, F. Olsson, H. W. Persson, and T. Jansson, “Frequency- and Phase-Sensitive
Magnetomotive Ultrasound Imaging of Superparamagnetic Iron Oxide Nanoparticles,” IEEE Trans. UFFC, vol 60, no.3, pp
481-491, 2013.
23
3C2
ULTRASOUND SPECKLE TRACKING FOR ARTERIAL STRAIN IMAGING – A VALIDATION
STUDY IN-SILICO, IN-VITRO AND IN-VIVO
1,2
1
2
1
2
Matilda Larsson , Brecht Heyde , Lars-Åke Brodin , Jan D’hooge
KTH-Royal Institute of Technology, School of Technology and Health, Stockholm, Sweden.
2
Department of Cardiovascular Sciences, KU Leuven, Leuven, Belgium
1. Introduction
Ultrasound-based speckle tracking for estimation of arterial wall strain has potential to be used for assessment of arterial
stiffness to improve cardiovascular risk stratification. However, most speckle tracking algorithms have been developed and
validated for cardiac applications, whereas strain assessment in the artery wall is more challenging due to lower strain
amplitudes combined with poor spatial resolution. This project aimed to develop and test an ultrasound-based speckle
tracking algorithm for strain estimation of the artery wall in simulated data sets, in an experimental setup and in an animal
model.
2. Method
A speckle tracking algorithm tuned for the vascular setting was developed in Matlab (normalized cross-correlation for 2D
motion estimation across frames, kernel size: 5λ×2λ, axial and lateral kernel overlap: 40% and spline interpolation for subsample motion detection). Accumulation of the displacement maps throughout the cardiac cycle was performed and
longitudinal and radial strains were then obtained by linear regression after averaging in one direction of the selected region
of interest (radially for longitudinal strain and vice versa). The strain curves were then drift compensated and low-pass
filtered. The speckle tracking algorithm was validated in three steps: in-silico, in-vitro and in-vivo. First, it was applied on
simulated ultrasound images from a kinematic cylindrical model of the carotid artery with realistic dimensions and
movement pattern. The ultrasound images were simulated using a generalized convolution model (COLE) with realistic
image properties and the estimated strain was then compared with the ground truth from the model. In the experimental
validation, the algorithm was applied on ultrasound images from polyvinyl alcohol phantoms mimicking the carotid artery.
The phantoms were connected to a pulsatile pump, programmed to generate carotid flow profiles. Sonomicrometry crystals
were glued on the phantom walls and used to acquire reference values of strain. In the in-vivo validation, the algorithm was
applied on ultrasound images obtained in a sheep model. The left carotid arteries of 3 sheep were exposed during isofluran
anesthesia and two sonomicrometry crystals were sutured onto the artery wall to obtain reference values of longitudinal
strain. The wound was closed and filled with ultrasound gel followed by ultrasound imaging at baseline and stress.
3. Results
An overall good agreement was found between the strain estimated with the speckle tracking algorithm and the reference
strain in the three validation setups. In-silico, the peak systolic radial strain was estimated to be -13.15 ± 0.99% (ground truth
13.89%) while longitudinal strain was 5.25 ± 1.20% (ground truth 5.30%). The correlation between estimated mean peak
strain values and reference peak strain values was r = 0.92 (p < 0.001) for radial strain and r = 0.72 (p = 0.006) for
longitudinal strain in the experimental setup. The results from the in-vivo validation are shown in Fig. 1.
4. Discussion
This study shows the feasibility of estimating radial and longitudinal strain in the carotid artery using ultrasound speckle
tracking. However, the step from in-silico and in-vitro to in-vivo estimation is challenging and the surgical exposure in the
in-vivo validation may have affected the artery wall properties since lower strain values than previously observed in-vivo
were obtained. Moreover, further studies are needed to test the algorithm on human in-vivo data and to investigate the
potential of the method to estimate arterial stiffness and detect cardiovascular diseases at an early stage.
24
3C4
ARTIC – ETT FLEXIBELT PROGRAM FÖR KARAKTERISERING AV ARTÄRER I
ULTRALJUDSBILDER
1
Simon Segstedt1, Tobias Nilsson1, Åsa Rydén Ahlgren2, Tomas Jansson3, Hans W Persson1, Magnus Cinthio1
Elektrisk Mätteknik, Lunds Tekniska Högskola, Lund 2Klinisk Fysiologi, Lunds Universitet, Malmö, 3Institutionen för Kliniska Vetenskaper,
Lund Universitet, Lund
1. Introduktion
Ultraljudsmätningar av diameter, distension och väggtjocklek (intima-media thickness, IMT) hos artärer med hjälp av
ultraljud är en viktig metod inom kardiovaskulär forskning. Vi har utvecklat en automatisk metod, ARTerIal Characterization
(ARTIC), för att mäta diameter, distension och IMT, där målet har varit att göra en generell och lättanvänd metod som
fungerar på så många olika typer av kärl som möjligt. Tidigare utvärderingar har gjorts på halspulsådern med filformat som
är specifika för var ultraljudsapparat. I denna utvärdering har vi studerat det standardiserade bildformatet (DICOM) samt
studerat flera andra kärl.
2. Metod
ARTIC är baserad på segmentering där de olika lagren i kärlväggen detekteras med hög upplösning, se figur 1. Till skillnad
från standardiserade manuella mätningar där enskilda bilder används, mäter ARTIC diameter, distension och IMT i hela
bildsekvenser. Detta möjliggör automatisk mätning av diameter, distension och IMT under hela hjärtcykeln. Vi har tidigare
gjort en utvärdering av ARTIC och jämfört den med en fantomvaliderad metod. I den utvärderingen användes bilder på
halspulsådern från både gamla och unga individer tagna med olika ultraljudsapparater. För att kunna implementeras i större
vetenskapliga studier har vi nu också gjort en utvärdering med DICOM-bilder. Dessutom har vi gjort en inledande
utvärdering där ARTIC har använts för att mäta diameter, distension och IMT hos aorta, brachialis och poplitea. I DICOMutvärderingen mättes halspulsådern med två olika frekvenser, 9 MHz (12 individer, medelålder 39 år, 25-54 år) och 12 MHz
(20 individer, medelålder 41 år, 21-62 år). I den andra utvärderingen mättes totalt 10 kärl hos 6 individer (medelålder 38 år,
27-62 år). Varje kärl mättes två gånger varpå repeterbarheten mättes med hjälp av coefficient of variation (CV).
3. Resultat
DICOM-utvärderingen visade CV-värden på 0.6% för diameter (medel±SD 5613±562 µm), 3.9% för distension (604±145
µm) och 3.2% för IMT (592±91 µm) för 9 MHz samt 0.7% för diameter (5466±534 µm), 4.2% för distension (566±166 µm)
och 2.4% för IMT (609±86 µm) för 12 MHz. Utvärderingen av olika kärl gav CV-värden på 0.9% för diameter (6812±4149
µm), 13,1% för distension (368±472 µm) och 2.8% för IMT (514±240 µm).
4. Diskussion
Utvärderingarna, i kombination med tidigare studier [1, 2], visar att ARTIC är en generell metod som fungerar för olika typer
av bilder och olika typer av kärl. Parametrarna beräknas automatiskt efter att operatören markerat blodkärlets mitt med ett
musklick. Beräkningstiden är kort (~1ms/bildruta) och ett flertal markörer för kardiovaskulär hälsa kan sparas. Även andra
funktioner finns implementerade, såsom möjligheten till manuell mätning och uppskattning av lokalt tryck, i t.ex. aorta, med
hjälp av den beräknade distensionskurvan [3]. Genom att vara en generell och användarvänlig metod kommer ARTIC kunna
vara ett värdefullt hjälpmedel inom kardiovaskulär forskning.
Figur 1. Till vänster visas en ultraljudsbild (DICOM) där de olika lagren är markerade med svart (adventitia) respektive vitt
(intima). Till höger visas resultatet, heldragen linje markerar diameter-resultat och streckad linje markerar IMT-resultat.
Referenser
[1]
T. Nilsson, S. Segstedt, Å. R. Ahlgren, S. Ricci, G. Östling, P. Tortoli, J. Nilsson, T. Jansson, H. W. Persson, and
M. Cinthio, "A robust and fast method for arterial lumen diameter and intima-media thickness measurements," in
IEEE Ultrasonics Symposium, 2012, p. In Press.
[2]
S. Segstedt, T. Nilsson, P. Milton, S. Sveinsdottir, T. Jansson, H. W. Persson, D. Ley, and M. Cinthio, "Arterial
diameter change measurements in premature rabbit pups using B-Mode images," in IEEE Ultrasonics Symposium,
2012, p. In Press.
[3]
J. Kips, F. Vanmolkot, D. Mahieu, S. Vermeersch, I. Fabry, J. de Hoon, L. Van Bortel, and P. Segers, "The use of
diameter distension waveforms as an alternative for tonometric pressure to assess carotid blood pressure,"
Physiological Measurement, vol. 31, pp. 543-553, Apr 2010.
25
3C6
A FAST 2D TISSUE MOTION ESTIMATOR BASED ON THE PHASE OF THE INTENSITY
ENABLES VISUALIZATION OF THE PROPAGATION OF THE LONGITUDINAL MOVEMENT IN
THE CAROTID ARTERY WALL
1
Tobias Nilsson , Åsa Rydén Ahlgren2, John Albinsson1, Simon Segstedt1, Jan Nilsson2, Tomas Jansson3, Hans W Persson1, Magnus
Cinthio1
1
2
Electrical Measurements, Faculty of Engineering, LTH, Lund University, Sweden. Department of Clinical Sciences Malmö, Lund
3
University, Sweden. Department of Clinical Sciences Lund, Lund University, Sweden.
1. Introduction
A fast 2D motion estimator applied on ultrasound B-mode images has been developed and evaluated. As oppose to most
other methods this method does not utilize block-matching or iterative solutions. The method is thus computationally
efficient and suitable for real-time motion estimation over the entire image. Further the method has enabled visualization of
the propagation of the longitudinal movement in the carotid artery wall.
2. Method
The 2D motion estimator converted the B-mode intensity to phase information in the vertical and horizontal directions. For
each direction, the intensity was first differentiated and the Hilbert transform was applied to extract the spatial phase. Then
the average temporal phase difference between two frames and the average spatial phase gradient was calculated using a
convolution with a 2D kernel of ones. The motion of each pixel was then calculated as the quotient between these two
matrices. The method has been evaluated on 1) phantom measurements and 2) in vivo on the carotid artery wall of 17
subjects, where measurements of the longitudinal displacement of the intima-media complex were compared to our
previously validated method.
3. Results
The error of the phantom measurements was 1.6±15.7% (velocities between 5-10 mm/s; approx. 9.5 million estimations). In
the in vivo measurements the mean difference (validated-proposed) was 18±44µm. Several different phases of the
longitudinal propagation, which seem to be connected to the multi-phasic pattern of the longitudinal movement, can be seen.
All phases of the longitudinal propagation seem to originate from the direction of the heart. Figure 1 show four consecutive
frames (FR = 54 Hz; kernel size ~1x1 mm) where two phases of the propagation of the longitudinal movement can be
visualized.
4. Discussion
In conclusion, conversion of B-mode intensity to spatial phase information enables fast tissue motion estimation in two
dimensions. The method is simple and well suited for real time implementation for tracking in entire images in various
applications. An interesting application is the visualization of the propagation of the longitudinal movement in the carotid
artery wall which, to our knowledge, has not been visualized before. All phases during a cardiac cycle seem to originate from
the direction of the heart.
Figure 1: Four consecutive frames (A-D) of a carotid artery. The horizontal velocity of the longitudinal movement is colorcoded and overlaid on the grey-scale image. In these frames, two phases of the propagation of the longitudinal movement can
be visualized, one with negative velocity and one with positive velocity relative to the heart. The direction of the heart is to
the right.
26
Sammanfattningar
Mätteknik
Session 4C
Moderator: Gösta Hellström
27
27
4C1
COMPREHENSIVE ASSESSMENT OF LEFT VENTRICULAR RELATIVE PRESSURE FIELDS
1
1
2
Jonatan Eriksson , Ann F Bolger , Carl-Johan Carlhäll1, Tino Ebbers1
2
Linköpings University and Center for Medical and Image Science (CMIV), Linköping, Sweden. Department of Medicine, University of
California, San Francisco, California, USA
Introduction
Blood flow within the cardiovascular system is driven by pressure differences, where blood accelerates from higher to lower
pressure areas. Absolute pressure may not be measured non-invasively, but relative pressure fields can be calculated from
velocity fields [1] acquired using MRI or ultrasound. Although relative pressure fields may be visually analyzed, such
assessment is highly user dependent and qualitative. In this study we utilized pressure fields based on three-dimensional,
three-directional, time-resolved (3D + time = 4D) MRI (magnetic resonance imaging) data to investigate the distribution of
pressure gradients in the left heart and present a comprehensive analysis approach.
Methods
Ten healthy subjects underwent an MRI examination (1.5T, Philips Achieva) where 4D velocity
and morphological data were acquired. Time-resolved velocity data was acquired in a 3D volume
encompassing the heart with a spatial resolution of 3x3x3 mm3 and a temporal resolution of 50.4
ms. Data was reconstructed into 40 time frames and corrections were made for concomitant
gradient field effects on the scanner. In-house written Matlab software was used to correct for
background errors and phase-wraps.
The left ventricle (LV) and atrium (LA) were segmented based on the morphological short axis
images at all diastolic time frames and LV only during the systolic time frames, using freely
available software, Segment (http://segment.heiberg.se). The segmentation was used as boundary
condition for computation of the 4D relative pressure fields from the pressure Poisson equation.
Computations were performed by the use of a multigrid solver [2]. The LV blood pool was
divided into 17 segments in a similar way fashion as customary for myocardial assessment [3].In
short, the segments are defined based on 4 short axis slices covering the LV from apex to base.
The slice through the apex contains one segment. The basal and mid slices were divided into six
60 degrees pie segments, while the remaining apical segment was divided into four 90 degrees
segments. The median and range of the pressure was computed for every segment, after the
median pressure of the 17th segment (apex) was subtracted from the pressures of the other
segments.
Figure 1. Relative
pressure fields in a
three-chamber view
at time of peak early
filling. A healthy 50
y.o. female with a
heart rate of 66 bpm.
Pressure
is
in
mmHg. LV, Left
Ventricle; LA, Left
Atrium.
Results
For every subject, the median pressure in all
segments, except the apex, were plotted over the
cardiac cycle (figure 3). Distinct positive and
negative pressure gradients could be recognized
during the acceleration and deceleration
respectively, of both early and late diastolic LV
filling, as well as during LV ejection. For interesting phases, as early filling,
the median and range of the pressures were visualized in a so-called bullseye
plot (figure 2). The bullseye plots clearly showed that the main pressure
gradients were directed in the base-apex direction, while the pressure
differences within the short axis were considerable smaller.
Discussion
Visual assessment of time-resolved intracardiac velocity vector
fields is user dependent and time consuming. Computation of
3D relative pressure fields, which are scalar field, may present
a deobfuscated comprehensive approach for analysis of
intracardiac blood flow dynamics and may open
the doors for larger clinical studies of function.
References
[1] Ebbers T et al. Estimation of relative
cardiovascular pressures using time-resolved
three-dimensional phase contrast MRI. Magn
Reson Med 2001;45(5):872-879.
[2] Ebbers T and Farnebäck G. Improving
computation of cardiovascular relative pressure
fields from velocity MRI. J Magn Reson
Imaging 2009;30(1):54-61
[3] Cerqueira MD et al. Standardized
myocardial segmentation and nomenclature for
tomographic imaging of the heart. Int J
Figure 3. Median for all segments minus apex over time, in mmHg.
Cardiovasc Imaging 18: 539-542, 2002.
Black lines, basal segments; Red lines, mid segments; Magenta lines,
apical segments. Subject is a 50 y.o. healthy female.
Figure 2. Bullseye-plot showing a time frame of early
filling in a representative 50 year old female. The
median of apex are subtracted from all the segments.
Each segment is represented by median and range.
28
4C2
STEGRÄKNAR-APPAR FÖR ATT FRÄMJA FOLKHÄLSAN - MEN MÄTER DE RÄTT?
Anna Åkerberg1, Mia Folke1, Anne Söderlund2, Maria Lindén1
Mälardalens Högskola, Akademin för Innovation, Design och Teknik, Västerås, Sweden
2
Mälardalens Högskola, Akademin för Hälsa, Vård och Välfärd, Västerås, Sweden
1
1. Bakgrund
Fast forskning visar att det är farligt för hälsan att ha en stillasittande livsstil [1], blir människor mer fysiskt inaktiva i många
länder [2]. Det är väl känt att fysisk aktivitet har positiva effekter på kroppen [3-4], minskar risken för kroniska sjukdomar
[5], samt har positiv påverkan på en mängd medicinska tillstånd [6]. Ett vanligt sätt att mäta fysisk aktivitet är med
stegräknare, vilka har påvisat samband med ökad fysisk aktivitet [7]. Idag använder de flesta mobiltelefon och stegräknarappar möjliggör att dessa mobiltelefoner kan användas som stegräknare. Det saknas idag underlag för huruvida stegräknarappar mäter korrekt, vilket är en förutsättning för att kunna motivera till ökad fysisk aktivitet. Syftet med studien var att
utvärdera noggrannhet i mätning av sex stegräknar-appar för tre mobiltelefoner, vilka bars på tre olika positioner.
2. Metod
Tio testpersoner (5 kvinnor/5 män), medelålder 38 år (23-51), medel BMI 25.8 (19.9-36.6) och medellängd 1.76 m (1.671.92), gick 200 steg nio gånger i normal gånghastighet på en plan och rak väg. Stegen räknades manuellt, distansen mättes
med mäthjul och tiden klockades med stoppur. Tre mobiltelefoner användes; Iphone 4 (Apple Inc., USA), HTC Sensation
(HTC Corp., Taiwan) och Sony Ericsson Xperia Arc (Sony Mobile Com., UK/Sverige). Sex stegräknar-appar testades, varav
tre var utvecklade för Iphone och utvärderades endast på Iphone; Ipedometer LITE (app 1), Pedometer Ultimate GPS+ (app
2) och Pedometer 24/7 FREE (app 3). Resterande tre var kompatibla med både HTC och Sony E, och utvärderades därför på
båda androidtelefonerna; Pedometer by LexApps (app 4), Pedometer Levente Bagi (app 5) och Pedometer Luminant
Software Inc. (app 6). Samtliga appar var tillgängliga för gratis nerladdning (laddades ner febr. 2012) och ansågs populära.
För app 2-5 var känsligheten ställbar, vilken ställdes till medium/medel. Mobiltelefonerna bars i höger jackficka, i höger
byxficka och i ett sportarmband på höger överarm.
3. Resultat
Tabell 1. Medel antal steg och SD för varje mobiltelefon, app och
position.
Testpersonerna höll i genomsnitt en fart på 1.6 m/s (1.4-1.9). I en
jämförelse mellan telefonerna mätte Iphone mest noggrant och den
överestimerade inte heller stegen någon gång. HTC mätte mer
varierat men oftast med högre SD. Sony E underestimerade stegen
grovt för alla appar och positioner (se tabell 1).
Mobiltelefon
Iphone
App
Nr
1
Iphone
2
Iphone
HTC
3
4
Bröstficka
124 ±96.8
Byxficka
152 ±140.8
Sportarmband
73 ±57.7
162 ±16.0
100 ±18.6
195 ±28.4
143 ±23.6
144 ±52.0
90 ±9.8
206 ±79.3
302 ±108.4
159 ±27.0
4. Diskussion
5
230 ±72.6
290 ±73.6
162 ±24.1
Majoriteten av apparna som utvärderats i denna studie klarade inte HTC
6
att utföra noggranna mätningar. Endast en kombination av HTC
128 ±57.8
139 ±90.6
145 ±61.1
mobiltelefon och app (Iphone med app 2) påvisade noggranna Sony E
4
2 ±2.7
12 ±12.6
4 ±6.0
mätningar med godtagbar SD, speciellt i byxfickan (195±28.4). En Sony E
5
3 ±1.9
43 ±92.8
15 ±14.8
svårighet med stegräknarappar är att mobiltelefonen kan bäras på ett
Sony E
6
14 ±29.6
81 ±54.4
74 ±58.6
flertal sätt, jämfört med traditionella stegräknare. Eventuell
inverkan av vinkeln på mobiltelefonen har därför undersökts, vilka visade att vinkeln kan ha betydelse för hur mobiltelefonen
registrerar stegen, men att utförligare studier behövs för att påvisa detta. En rekommendation är därför att mobiltelefonen
alltid skall bäras på samma sätt när den används som stegräknare [8]. Utvärderade stegräknar-appar kan bli praktiska,
trovärdiga och användbara redskap för att mäta fysisk aktivitet då en stor del av befolkningen som redan äger en mobiltelefon
då kan övervaka sin vardagliga fysiska aktivitet på ett korrekt sätt. Detta kan i ett vidare perspektiv främja folkhälsan.
Referenser
[1] P. Katzmarzyk, T. Church, C. Craig, C. Boouchard. Sitting Time and Mortality from All Causes, Cardiovascular Disease
and Cancer, Medicine in Science and Sports & Exercise, 42, 998-1005 (2009).
[2] WHO, Global Recommendations on Physical Activity for Health. Available from:
http://whqlibdoc.who.int/publications/2010/9789241599979_eng.pdf, latest access on 2013; Apr 18 (2010).
[3] WHO, Global Strategy on Diet, Physical Activity and Health. Available from:
http://www.who.int/dietphysicalactivity/strategy/eb11344/strategy_english_web.pdf, latest access on 2013; Apr 5 (2004).
[4] C. H. Hillman, K. I. Erickson, A. F. Kramer. Be smart, exercise your heart: exercise effects on brain and cognition,
Nature Reviews Neuroscience, 9, 58-65 (2008).
[5] ISPAH, The Toronto Charter for Physical Activity and Health: A Global Call for Action. Available from:
http://wwwcflri.ca/icpah/en/dokument/CharterDocument3 ENG draft3.pdf , latest access on 2013; Mars 10 (2010).
[6] K. Johansen, P. Painter. Exercise in individuals with CKD. American Journal of Kidney Diseases, 59, 126-134 (2012).
[7] D. M. Bravata, C. Smith-Spangler, V. Sundaram, A. L. Gienger, N. Lin, R. Lewis, C. D. Stave, I. Olkin, J. R. Sirard.
Using Pedometers to Increase Physical Activity and Improve Health: A systematic Review, JAMA, 298, 2296-2304 (2007).
[8] A. Åkerberg, M. Lindén, M. Folke. Pedometer Cell Phone Applications and Future Trends in Measuring Physical
Activity. In R. Martinho, R. Rijo, M. Cruz-Cunha, J. Varajão (Eds.), Information Systems and Technologies for Enhancing
Health and Social Care (pp. 324-339), latest access on 2013; April 25. doi:10.4018/978-1-4666-3667-5.ch021
29
29
4C3
Ett multifunktionelt mätsystem som kan efterlikna förhållanden under en stroke: hur försvarar sig
neuroner mot akut syrebrist?
1,2
1
1,2
1,2.3
Kerstin Ramser , Ahmed Alrifaiy , Olof A. Lindahl
2
3
Luleå Tekniska Universitet, Luleå, Sverige. CMTF, Center för Medicinsk Teknik och Fysik, Luleå och Umeå, Sverige. Norrlands
Universitetssjukhus, Umeå, Sweden.
1. Introduktion
På senare tid har aktuell forskning gett inblick i hur vår kropp fungerar på den biokemiska nivån. Det har lett till nya
terapeutiska strategier för att förhindra eller bota neurologiska sjukdomar såsom hjärncancer, stroke, Alzheimers och
Parkinsons. Framstegen beror till stor grad på utvecklandet av mätmetoder som ger kunskap om hur små organismer beter sig
på den biomolekylära nivån. Vår tvärvetenskapliga forskning är inriktad på att utveckla metoder för att undersöka hur
levande biologiska neuroner eller hjärnvävnad försvarar sig mot syrebrist eller andra stressituationer. Vi har inriktat oss på
hemoproteiner då det nyligen har visat sig att de kan förhindra skador som uppstår vid syrebrist. Vi sammankopplar ett flertal
mätmetoder och ett mikroflödessystem under ett mikroskop för att undersöka hemoproteiners verkan på enstaka neuroner i
nära fysiologiska miljöer, det vill säga så likt det levande som möjligt. Det har visat sig vara viktigt att kunna studera
nervcellernas elektriska signaler som är ett mått på stressnivån samtidigt som man mäter hur hemoproteiner samverkar med
olika molekyler och proteiner. De elektriska signaleringsegenskaperna hos nervceller eller tunna hjärnsnitt mäts lämpligen
genom patch-clamp teknik [1]. Optisk Raman spektroskopi och UV-Vis spektroskopi fungerar väl för att studera
haemoproteiner och de första Ramanmätningarna på tunna hjärnskivor visade att det går att skilja åt olika hemoproteiner [2].
För att kunna kontrollera syrehalten krävs det en sluten gastät flödeskammare med möjlighet till patch-clamp där man snabbt
kan flöda olika lösningar av varierande syre-, och salthalt. I detta system är patch-clamp pipetten fixerad till en position och
cellerna förs till pipetten med hjälp av en optisk pincett [3] som är en beröringsfri optisk manipuleringsmetod där biologiska
celler fångas i ett starkt fokuserat laserljus som här förflyttas med hjälp av ett xyz-bord. Vi kommer att presentera de senaste
framstegen i utvecklandet av mätsystemet där röda blodceller användes som modell.
2. Metod och resultat
Ca 10 microliter blod tappas ur fingret från en frivillig och blandas ut i fysiologisk fosfatbuffertlösning. Lösningen sattes in i
en spruta som kopplades till en kontinuerlig pump med ett flertal sprutor som reglerades genom individuellt programmerbara
tryckkolvar (Cetoni, Tyskland). Mikroflödessystemet i plexiglas (PMMA) ritades upp i ett CAD program och frästes i en
CNC styrd maskin. Mikroflödessystemet hade en kanal med en gastät ingång för patch-clamp pipetten som fördes in till en
fix position med en mikrometerskruv. Pipetten var dragen med en pipettdragare (Kopf750, David Kopf Instuments, USA) och fylldes med intracellulär lösning och en elektrod. Pipetten kopplades till pipetthållaren (Axon Digitada, USA) utrustad
med signalförstärkaren (Heka 7, Tyskland). Signalerna behandlades av mjukvara (pclamp 7, Axon, USA). Raman
spektrometern (Schamrock 303, Andor technology, UK, våglängd 532 och 830 nm) eller UV-Vis spektrometern (HR 400
Ocean Optics, USA) kopplades till sidoporten av det inverterade mikroskopet (IX71, 100x, 1.4 NA, Olympus, Japan).
Mikroflödessystemet sattes på xyz-bordet. Syrehalten kontrollerades genom att införa fysiologisk buffert med 0% eller 21 %
syrehalt, uppmätt av syresensorn (FOXY AL 300, Ocean Optics, USA), med en kontinuerlig peristaltisk pump (Knauer,
HPLC K-501, Knauer, Tyskland) in i mikroflödessystemet. Referenselektroden sattes i en utgångskanal som fungerade som
utlopp. En optisk pincett, bestående av en strålexpander (1:5) och en NIR laser (200mW, 808nm, IQ1A, Power Technology,
USA) tillfördes genom bakre ingången av mikroskopet. 3. Resultat och diskussion
Patch-clamp pipetten justerades till att generera en pipettspets som gav en resistans mellan 10-15 MΩ vilket motsvarar en
diameter som ligger under en micrometer, vilket är nödvändigt för att studera deformerbara röda blodceller. Pipetten sattes på
pipetthållaren som var kopplad till en vinklad mikrometerskruv. Genom mikrometerskruven kunde pipetten sättas i exakt och
fix position inne i kanalsystemet vilket observerades genom mikroskopet. Resistansen uppmättes och registrerades i
mjukvaran. Efter det kunde de röda blodcellerna lätt införas i systemet. Genom den optiska pincetten kunde de fångas och
föras fram till pipettspetsen där de med undertryck sögs fast vid pipettspetsen för att åstadkomma en hög resistans (200-1500
MΩ). Buffert med varierande syrehalt (21% - ca 0-1%) pumpades in i flödeskammaren till den röda blodcellen. Den minsta
uppmätta syrehalten låg mellan 0-1% vilket skall jämföras med tidigare mätningarna där den minsta syrehalten varit bäst 7%,
vilket motsvarar normala syrehaltnivåer i hjärnan. Detta är en klar förbättring. Optisk spektroskopi kunde utföras samtidigt
som den röda blodcellen var patchad, dvs fäst vid pipettspetsen. Experiment på att få en högre kontaktresistans för att kunna
utföra ett komplett protokoll för patch-clamp mätningar är pågående.
4. Slutsats
Framstegen med den första prototypen av den syretäta mikroflödeskammaren är lovande [4]. Syrehalten kunde sänkas rejält
jämfört med konventionella system. På så sätt blir mätningarna mer likt de förhållanden som råder i hjärnan under en stroke.
Det är viktigt för att kunna se i realtid hur hjärnan försvarar sig mot syrebrist och de första Ramanmätningarna har visat att
det är möjligt att studera hemoproteiner i realtid [2]. Vårt slutgiltiga mål är att förstå hur proteinet fungerar för att kunna
utveckla preventiva mediciner, som aktiverar eller bromsar Ngb, för att hjälpa människor i riskzonen för hjärncancer, stroke,
Alzheimers eller Parkinsons.
References
[1] E. Malinina, M. Druzin, K. Ramser, S.Johansson, 7th Forum of European NeuroScience FENS, Amsterdam, Netherlands, 2010, pp.
014.020.
[2] K. Ramser, E. Malinina, S. Candefjord, Applied Spectroscopy, 2010, 66(12), pp 1454-1600.
[3] K. Ramser, H. Dagtorp, Journal of Biophotonics, 2010, 3 (4), pp 187-206.
[4] A. Alrifay, K. Ramser, Biomedical Optics Express, 2012, 2(8), pp 2299-2306
30
4C5
DISPOSABLE CHIP TO ENABLE METERING IN DRIED BLOOD SPOT
SAMPLING
Gabriel Lenk1, Anton Pohanka2, Göran Stemme1, Olof Beck3, Niclas Roxhed1
1
Micro and Nanosystems, KTH Royal Institute of Technology, SWEDEN
2
Dept. of Laboratory Medicine, Karolinska Institutet, SWEDEN
3
Dept. of Medicine, Division of Clinical Pharmacology, Karolinska University Hospital, SWEDEN
This work presents a disposable chip for metering and transferring an exactly defined liquid volume into
a paper matrix using self-actuated dissolvable valves. Once a liquid droplet of 20-50 µl is applied to the chip,
a volume of 1 µl is automatically metered, separated from the applied volume and subsequently transferred into
conventional Whatman 903 paper used in Dried Blood Spot (DBS) sampling.
Background: With increased sensitivity in analysis techniques such as HPLC-MS/MS, DBS sampling is
considered to be a simple and convenient alternative to venous blood sampling, especially interesting for
Therapeutic Drug Monitoring (TDM) [1]. However, conventional DBS sampling stores an unknown volume
of blood from a fingerprick in a paper matrix, thus making quantitative analysis inaccurate. The problem
with quantitative analysis of DBS stems from the unknown volume that is stored in a punched out disk from the
spot. Inhomogeneous distribution of analytes within the spot is caused by hematocrit and chromatographic
effects in the paper [2,3]. An engineered solution to ensure exact blood volume sampling directly from a
fingerprick into conventional DBS paper has, to the best of our knowledge, not been reported yet.
This work: The chip we present consists of a combination of DBS paper, structured transparencies and a
dissolvable thin film (DTF). The DTF separates a microfluidic layer (inlet, channel, outlet) from a paper storage
layer and controls by its thickness the timing sequence of different events (fig.2). When a droplet is applied to
the chip inlet, capillary filling of a microchannel occurs which defines a precise volume. Once the barrier
between the microfluidic layer and the storage layer is broken up, the fluid is absorbed by the paper matrix. This
cause a pinch of at the beginning of the channel where the excess volume is first absorbed and separates the
defined volume, which is then sucked out from the channel through the outlet by the capillary forces in the paper
matrix. The whole stored spot at the outlet can now be punched out. Since the volume has been metered in the
microchannel, spot inhomogeneity is no longer a concern.
Results: From 64 tested chips 55 showed a successful filling sequence. Quantitative measurements using HPLCMS/MS showed metered dried liquid spots (DI-water spiked with amphetamine) with a volume of 0.86 µl
(±0.099 µl). The working principle was also demonstrated with blood from a fingerprick.
Conclusion: This paper demonstrates a disposable and accurate low cost chip for microliter metering of liquid
samples into a DBS paper matrix. The presented method offer a viable solution to achieve quantitative
measurements from simple and convenient DBS sampling which may have an enormous impact on
individualized drug therapy and TDM.
[1] Edelbroek et al., Dried Blood Spot Method in Therapeutic Drug Monitoring: Methods, Assays, and Pitfalls., The Drug Monit. 2009.
[2] Spooner et al., Dried Blood Spots as a Sample Collection Technique of pharmcokinteics in Clinical Studies…, Anal Chem, 2009
[3] O`Mara et al., The effect of hematocrit and punch location on assay bias during quantitative bioanalysis of DBS samples, Bioanal, 2011.
Figure 1: Comparision of DBS on Whatman 903.
Left side: a DBS paper with the punch taken from
its center, the dark outline of the spot indicates
inhomogeneous spot properties. On the right:
punched out chip-DBS of ~1 μl, the whole outline
of the spot is on the sampled disk.
31
Figure 2: Illustration of the metering sequence
showing the cross-section of the chip with the
corresponding top view picture during application
of a undefined blood volume from a fingertip. The
chip extracts a defined volume from the applied
droplet, separates it and transfers it to the paper
matrix.
31
4C6
VIRTUELL VIT KÄPP FÖR DEN SEENDE RULLSTOLEN
1
2
2
2
Daniel Innala Ahlmark , Maria Prellwitz , Jenny Röding , Lars Nyberg , Kalevi Hyyppä
1
2
Institutionen för system- och rymdteknik Institutionen för hälsovetenskap
Luleå tekniska universitet
1. Bakgrund
Att ge sig ut på okända platser är en stor utmaning för
synskadade. Färdtjänst och ledsagarservice underlättar,
men då krävs tidig planering för varje utflykt. Detta kan
resultera i att man helt enkelt hoppar över vissa utflykter
man annars skulle tänkas göra.
Vi utvecklar en virtuell vit käpp som kan användas för
att på flera meters avstånd och utan fysisk kontakt
upptäcka hinder och riktmärken i omgivningen. Detta gör
att man får en bättre överblick över ett större område, i
likhet med hur synen används. Med denna information
blir det lättare att hålla koll på var man är och vart man
ska.
Många navigationshjälpmedel för synskadade har
utvecklats men ytterst få används. Detta kan bero på att
de är för svåra eller ansträngande att använda i
förhållande till vad de tillför, eller att den underliggande
tekniken inte är eller upplevs tillräckligt tillförlitlig. Ett
lättanvänt och tillförlitligt navigationshjälpmedel bör leda
till ökad trygghet, möjlighet till en mer spontan livsstil,
sänkt ledsagarbehov och bättre livskvalitet.
2. Vår lösning
Systemet bygger på ett naturligt användningssätt som
påminner om den vita käppen. Detta bör resultera i att
systemet är lättare att lära sig använda och lita på. Det
använder varken GPS eller kartinformation och kan
därmed användas överallt och utan oro över att systemets
karta inte stämmer med verkligheten. Vi låter synskadade
användare utvärdera systemet tidigt och påverka
utvecklingsprocessen. Detta görs i samarbete med
forskare från institutionen för hälsovetenskap vid Luleå
tekniska universitet.
3. En första utvärdering
En handfull synskadade personer har testat systemet.
Syftet med detta var framför allt att avgöra huruvida det
är intuitivt att ta till sig och använda information om
närliggande hinder via haptik. Försökspersonerna
observerades och intervjuades efteråt. På detta sätt
framkom många värdefulla synpunkter för framtida
utveckling av systemet.
4. Resultat
Försökspersonerna var alla vana vid den vanliga vita
käppen. Detta märktes i hur snabbt de förstod och började
använda systemet. Ingen uttryckte otrygghet, men en del
kommenterade att det krävdes mycket koncentration att
använda systemet. Att bedöma avstånd till hinder
upplevdes som svårt, troligen främst på grund av att de
aldrig testat systemet tidigare. Att kunna känna på ett
längre avstånd sågs som den primära nyttan med
systemet. Fortsatt forskning kommer fokusera på en
bärbar enhet som bygger på liknande användningssätt.
32
1
Figur 1: Laserskannern mäter avstånd till föremål i
omgivningen.
Figur 2: En förenklad 3D-modell av omgivningen
skapas.
Figur 3: 3D-modellen upplevs via känseln, med hjälp
av en haptisk robot.
Sammanfattningar
Medicinska Bilder II
Session 1D
Moderator: Anna Bjällmark
33
1D1
A NEW METHOD FOR OBTAINING HIGH-RESOLUTION VELOCITY DATA
FROM MAGNETIC RESONANCE IMAGING?
Jonas Lantz, Tino Ebbers
Department of Science and Technology (ITN), and Center for Medical Image Science and Visualization (CMIV), Linköping University
1. Introduction
With phase-contrast magnetic resonance imaging (PC-MRI), it is possible to measure blood flow in vivo. Besides the three
velocity components, it has also been shown that the turbulent kinetic energy can obtained [1]. The spatial resolution of flow
measurements is typically on the order of millimetres, while the temporal resolution is on the order of 20-40 milliseconds. In
addition to the relatively low resolution (15-20 voxels over a typical aortic diameter), partial-volume effects close to the
arterial wall can have a detrimental effect on the flow measurement. In order to obtain high-resolution MRI-data, naïve
interpolation between measurement points will not reproduce small flow scales, but instead introduce unphysical flow
features and violate conservation of mass and momentum. To overcome this, and obtain high-resolution MRI-data, we here
present a new method of obtaining a high-resolution flow field from PC-MRI-measurements using the governing flow
equations to fill in the gaps, while at the same time obey the laws of physics.
2. Method
The Navier-Stokes equations are the governing equations for any flow field and completely describe
the fluid flow. They can be used to compute the flow field inside large vessels using 2D PC-MRI data
as inflow boundary conditions [2]. This approach, computational fluid dynamics (CFD), may become
inaccurate due to sensitivity to uncertainties in boundary conditions and unavoidable modelling
assumptions in the numerical algorithms, which makes its use challenging for complex flow fields due
to e.g. diseases. We developed a new technique, which utilizes the full potential of 4D flow MRI,
where internal conditions are used together with standard boundary conditions. These internal
conditions are based on the 4D PC-MRI measurement and act as momentum sources or sinks. In this
study, this approach was tested on a part of the abdominal aorta with a renal artery, see Figure 1. The
time-resolved 3D velocity field and anatomy were measured using a 1.5 T Philips Achieva MRI
system. From this measurement, a time-resolved 3D high-resolution velocity field was computed using
the proposed approach. For comparison, a conventional CFD simulation was performed, utilizing
solely the inflow boundary condition from PC-MRI. The simulation software was Ansys CFX 14.5.
Figure 1:
Surface
of
the
artery in the study.
3. Results
Initial results are presented in Figure 2, where it can be seen that the MRI-enhanced CFD simulation with internal conditions
agree better with the MRI simulation compared with the standard CFD simulation that only used MRI-data as boundary
conditions.
[m/s]
Figure 2: Cross-section of the artery just proximal the branching renal vessel (see Figure 1), color showing velocity
magnitude at peak flow rate. Left: MRI measurement, middle: MRI-enhanced CFD simulation, right: conventional CFD
simulation.
4. Discussion
The initial results show that the method may allow for enhancement of time-resolved 3D flow MRI data and yields the
expected effects. The MRI-enhanced flow field corresponds to the MRI-measured flow, while the conventional CFD
simulation gives a somewhat different velocity distribution. In addition to the enhanced MRI-data, flow parameters such as
wall shear stress, which is very sensitive to the near-wall resolution as it depends on the velocity gradient at the wall, can
easily be computed directly from the PC-MRI data without any assumptions on the velocity profile. This study shows the
potential of this approach for PC-MRI, but may also be used in combination with other imaging techniques such as
ultrasound Doppler. Further research is necessary to extend and evaluate this approach for other geometries, noisy data, data
with artefacts due to e.g. the present of prosthetic devices, and turbulent flow.
References
[1] P. Dyverfeldt et al. MRM 28, p 655-663, 2008
[2] J. Lantz et al. J Biomech Eng. 45, 537-542, 2012
34
1D2
Intra-Cardiac 4D flow MRI using spiral k-space trajectories
1
S. Petersson1, A. Sigfridsson2, C. Carhäll1, T. Ebbers1
2
Linköpings universitet, Linköping, Sweden. ETH Zürich, Zürich, Switzerland
1. Introduction
Time-resolved three-dimensional phase contrast MRI (4D flow) is a powerful tool for hemodynamic assessment in the
cardiovascular system. However, the application of the method has been hindered by long scan times. By using spiral k-space
trajectories, improved efficiency provides a means of reducing scan times without decreasing SNR. Spiral readouts have
previously been used for 4D flow measurements in the aorta using prospective ECG gating [1]. Using retrospective gating,
the entire cardiac cycle is covered, which allows analysis of late diastole and tracking of blood over a complete cardiac cycle.
These are crucial for cardiac 4D flow studies, and allow for pathline based data quality assessment.
The aim of this work is to develop a retrospectively gated 4D flow sequence using a stack of spiral readouts for the
measurement of intra-cardiac velocities.
2. Methods
A retrospectively gated 4D flow sequence using a stack of spirals was implemented on a Philips Achieva 1.5T. Six healthy
volunteers (age 28±3 years) were imaged. The following parameters were used for the spiral measurements: field of view
280x280x101-112 mm3; voxel-size 2.8 mm isotropic; VENC 1.2 m/s; temporal resolution 48 ms; spiral duration 5.5 ms; 10
spiral interleaves. A Cartesian scan with the same spatial resolution using a SENSE reduction factor of 2 was carried out for
comparison.
The data quality was evaluated by comparison with 2D through–plane velocity measurements in the proximal ascending
aorta and quantitative pathline analysis. Pathlines were released backward and forward from the left ventricle (LV) to
compute inflow and outflow volumes for the LV [2]; a small difference between the inflow and outflow values indicates
good data quality. Furthermore, to facilitate aortic flow comparison, the 4D flow data was reformatted to the same slice
location as the 2D data.
3. Results
Using spiral k-space trajectories, a 57% reduction in scan time could be achieved compared to the Cartesian scan, as shown
in Table 1. Comparison with the 2D through-plane measurement does not show any decrease in data quality. The outflow
values from the pathline analysis were slightly lower for some of the spiral acquisitions. Visual inspection of the pathlines
did not reveal any major differences in data quality (see Figure 1).
Table 1. Results for 6 healthy volunteers (mean ± std).
Scan time [min]
|Outflow-Inflow| [ml]
Spiral
13±3
7.7±7.5
Cartesian
30±7
4.9±3.7
Inflow [ml]
91±21
Outflow [ml]
84±22
Aortic flow [ml]
92±12
91±16
89±16
91±11
2D Cartesian
-
-
93±20
-
-
Figure 1: Pathlines
visualizing the blood
flow going from the
left atrium, trough
the ventricle, out in
the aorta from 4D
flow measurements
from one of the
healthy volunteers
using
a)
spiral
readouts and b)
Cartesian readouts.
4. Conclusion
A retrospectively gated spiral 4D flow sequence was successfully implemented. The spiral readouts resulted in more than a
two-fold reduction in scan time compared to a conventional Cartesian scan, which was already accelerated using parallel
imaging, without any notable loss in data quality. Additional improvements in scan time and resolution can be obtained by
using parallel imaging.
References [1] Sigfridsson MRM 2012 [2] Eriksson JCMR 2010
35
1D3
BLOCK-MATCHING METHODOLOGIES USING BLOCK EXPANSION IN THE TIME DOMAIN
FOR IMPROVED SPATIAL RESOLUTION AND INCREASED ROBUSTNESS –
AN IN VIVO EVALUATION
1
1
2
1
John Albinsson , Åsa Rydén Ahlgren , Magnus Cinthio
2
Electrical Measurements, Lund University, Lund, Sweden. Clinical Physiology, Lund University, Malmö, Sweden.
1. Introduction
The dynamics of the arterial wall is an important component of the dynamics of the cardiovascular system and an important
investigative tool for studying the effects of vascular disease and aging. The radial movement, i.e. arterial diameter change,
has been extensively investigated by ultrasound since the 1970’s and forms the basis for estimation of arterial wall stiffness.
Presently, measurement of the longitudinal movement of the arterial wall has shown a distinct bi-directional multi-phasic
movement of the same magnitude as the diameter change in the common carotid artery. Moreover, the inner layers of the
arterial wall showed a larger movement than the outer layer thus introducing an intramural shearing in the arterial wall.
We propose the hypothesis that the use of an extra block will lead to motion estimations in ultrasound B-mode images with
an increased spatial resolution while the accuracy is maintained. The hypothesis was tested on clinical ultrasound cineloops
consisting of in vivo measurements of the longitudinal movements of the intima-media complex of the common carotid
artery. The motion estimation was compared to both the basic method without use of an extra block and to our golden
standard method [1] for measurement of the longitudinal movement of the arterial wall.
2. Method
The basic tracking method [2] incorporated 1) a sparse iterative block-matching algorithm and 2) a sub-pixel determination
method. The primary block was expanded in the time domain by use of the information the block had in the previous frame.
A full-search block-matching scheme for the extra block was conducted within a limited search range (±2 pixels). The two
resulting positions (not necessarily the same) were used for sequent sub-pixel determination. The position of the tracked
block was then calculated as the spatially averaged sub-pixel position over both blocks. The size of the blocks was set
individually and independently by the operator for each tracking method and cineloop to obtain an acceptable level of
tracking accuracy. The size of the primary block and the extra block were equal in each measurement.
The common carotid artery on the right side of the volunteers was scanned in the longitudinal direction with a horizontal
orientation in the image. On each of the 20 healthy volunteers (10 males; age 27–57 years and 10 females; age 25–49 years),
two independent measurements were made. Electrocardiogram was recorded during all the measurements. All investigations
were performed with a commercial ultrasound system (HDI5000, Philips Medical Systems, Bothell, WA, USA).
3. Result
In the in vivo measurements (n = 40) the antegrade movement, i.e., a
displacement in the direction of the blood flow, in early systole was
mean 312 µm (SD 197) using the basic method with the use of an extra
block. The following retrograde movement, i.e., a displacement in the
direction opposite of the blood flow, was mean -706 µm (SD 222). The
subsequent antegrade movement was mean 577 µm (SD 218). The intraobserver variation (CV) was 22%, 18% and 22% for the different phases
of movement, respectively, using the basic tracking method and 21%,
13% and 17%, respectively, using the basic tracking method with the use
of an extra block. Though the mean area of the block was decreased, the
intra-observer variation when using the basic method was maintained
when the basic method with the use of an extra block is used. Using the
Figure 1: Difference against mean for the
basic method, the area of the block was mean 0.31 mm2 (SD 0.13) in the
measurements of the three major longitudinal
2
range of 0.15–0.76 mm , whereas using the basic method with the use of
displacements.
an extra block, the area of the block was mean 0.25 mm2 (SD 0.09) in
2
the range of 0.09–0.51 mm . This equals a decrease in the area of the block by 19% (p<0.01). Figure 1 shows the difference
against the mean between the basic method using an extra block and the golden standard method. Six cineloops were
excluded as they contained no specific echo structure with enough stability and thus the golden standard method was not able
to track the echoes in them.
4. Discussion
The incorporation of an extra block in the tracking was hypothesized in this study to increase the spatial resolution of a
tracking method while maintaining the tracking accuracy. The basic method with the use of an extra block was compared to
our golden standard method; a tracking method specialized for estimating arterial wall movements. The estimated
movements of the two methods are compared in Figure 1. Reported CV values for the golden standard method are 14%, 13%,
and 16% for the first antegrade, the retrograde, and the second antegrade movement respectively [3]. The figure and the CVvalues show that the basic method with the use of an extra block has a tracking accuracy of the same magnitude as the golden
standard method without any discernible bias. As can be seen, the golden standard method gave CV-values that are lower
than those from the proposed method, but with a higher demand on the stability of the echo structures in the cineloops. In six
of the 40 in vivo cineloops, the stability of the echo structures was too low for the golden standard method to successfully
estimate the movements. Please note that the proposed method successfully estimated the movements in these cineloops.
References
[1] M. Cinthio, Å. R. Ahlgren, T. Jansson, A. Eriksson, H. W. Persson, and K. Lindström, IEEE Trans. Ultrason.
Ferroelectr. Freq. Control, 52, 1300-1311 (2005).
[2] J. Albinsson, S. Brorsson, F. Lindgren, Å. R. Ahlgren, and M. Cinthio, Proc. IEEE Ultrason. Symp., 2000-2003 (2010).
[3] M. Cinthio and Å. R. Ahlgren, Ultrasound Med. Biol., 36, 697-704 (2010).
36
1D4
IMAGE ENHANCEMENT AND REDUCTION OF RADIATION DOSE FOR PANORAMIC DENTAL
X-RAY IMAGING
1
1
Hamed Hamid Muhammed
School of Technology and Health (STH), Royal Institute of Technology (KTH), Alfred Nobel Allé 10, SE-141 52 Huddinge, Sweden
Keywords: Image enhancement, X-ray dose, PCI-operation, panoramic dental X-ray
1. Background
Reducing the X-ray dose too much produces images with low quality; Noisy, blurred, faded, under exposed. The approach
used in this work aims at enhancing image quality by using advanced automatic image processing algorithms.
2. Purpose
To minimize X-ray dose exposure during panoramic dental X-ray imaging, in addition to automatically enhancing the
acquired X-ray images to achieve high quality images that can be viewed using ordinary monitors.
3. Method
An automatic, adaptive image enhancement algorithm was developed and implemented on multi-core CPU as well as GPU to
achieve real time performance.
4. Results
The method was tested on panoramic dental X-ray images acquired with varying radiation dose. The results were promising
and indicated the possibility of obtaining diagnostically usable images using a reduced dose by 50%. A group of ten dentists
and specialists evaluated the resulted images. Figure (1) shows a comparison between an enhanced panoramic dental X-ray
acquired with reduced dose by 50% and an original (unprocessed) panoramic dental X-ray acquired with a standard dose.
5. Discussion and conclusions
This study shows the possibility to achieve a number of goals that can lead to better patient safety and better healthcare in
general, such as:
•
•
Minimized X-ray dose to the patient, which can lead to reduced risk of physical damage (e.g. cancer) and psycological
consequences (e.g. stress).
Better image quality which can lead to better, faster and more accurate and confident diagnostic.
The resulted enhanced images can be automatically produced without any noticeable waiting time and viewed using any
ordinary monitor (LCD/LED TV or computer screens) without any need for any expensive/exclusive high-dynamic-range
displays.
Figure 1: comparison between (a) an enhanced panoramic dental X-ray acquired with reduced dose and (a) another original
one acquired with a standard dose.
37
1D5
MICROWAVE IMAGING SYSTEM UNDER DEVELOPMENT FOR BREAST CANCER DETECTION
1
1
1
Andreas Fhager , Mikael Persson
Chalmers University of Technology, Göteborg, Sweden
Abstract
Microwave imaging for breast cancer detection is investigated. Through numerical and experimental studies an imaging
system has been studied and evaluated for use in breast cancer imaging. Results are promising and clinical trials are within
reach.
Keywords: microwave imaging, breast cancer, image reconstruction
1. Introduction
Breast cancer is a serious health problem for women. According to national statistics of Sweden from year 2007 it is the most
common cause of death from cancer among women, with about 30 yearly deaths per 100,000 inhabitants, (1). The standard
method for breast cancer diagnosis today is X-ray mammography. Despite its recognized ability to detect tumors it suffers
from some limitations. Neither the false positive nor the false negative detection rates are negligible. This leads to a number
of unnecessary additional investigations and, more seriously, a fraction of the tumors are not detected at an early stage which
is a prerequisite for efficient treatment. An interesting alternative being researched extensively today is microwave
tomography. From measurements on excised tissue a significant dielectric contrast has been observed between the healthy
and malignant tissue.
2. Theory
In microwave tomography the object under investigation is surrounded by a number of transmitting and receiving antennas.
In the measurements each antenna is operated as a transmitter as well as a receiver for every possible combination of
antennas. In this work an iterative algorithm has been used for reconstructing the dielectric parameters of the target object
under test. It is based on electromagnetic simulations of the antenna system and the image is reconstructed based on a
comparison with the scattering measurements of pulses for the different transmitter/receiver combinations. The difference
between the measured and the simulated signals is used to update the dielectric properties in the target region. As the
reconstruction of the target object is iteratively refined, the simulated and measured signals converge. The assumption is that
when the difference is sufficiently small the reconstruction is completed.
4. Results and discussion
In this paper we will present results from our investigation and evaluation of the design of a clinical prototype for reaching
the performance required for accurate image reconstruction in the clinical situation. See figure 1 for an illustration of the
proposed imaging system.
5. Conclusions
There is a need for novel breast cancer detection systems to overcome the limitations with today’s modalities. Microwave
based system has the potential to become both sensitive and specific in this application. We have studied and evaluated a
possible design for a clinical system as well as developed an accurate image reconstruction algorithm to work with this
system.
References
[1] Sweden’s National Board of Health and Welfare: “Causes of death 2007”, (Access at: www.sos.se).
Figure 1: Illustration of the proposed microwave system.
38
1D6
A NEW METHOD FOR VESSEL SEGMENTATION BASED ON A PRIORI INPUT FROM MEDICAL
EXPERTISE IN PHASE-CONTRAST MAGNETIC RESONANCE IMAGING SEQUENCES
Sebastian Bidhult1, Marcus Carlsson1, Håkan Arheden1, Einar Heiberg1,2
Department of Clinical Physiology, Skåne University Hospital Lund, Lund University, Sweden.
2
Centre for Mathematical Sciences, Lund University, Sweden
1
Keywords: cardiovascular flow, segmentation, principal component analysis, magnetic resonance, active contours
1. Introduction
Phase contrast magnetic resonance imaging (PC-MRI) is the current gold standard for quantification of blood flow in the
cardiovascular system. Using this technique it is possible to quantify cardiac output, stroke volume, shunts and valve
insufficiencies. The accuracy of flow quantification is highly dependent on the manual delineation of the vessels of interest.
Therefore, the purpose of this study is to develop an automatic method for vessel segmentation in PC-MRI sequences.
2. Method
A total of 161 patients with ejection fraction below 40% from a previous study [1] were included. For all patients manual
delineations of the aorta ascendens were available in all timeframes. The subjects were randomly divided into a training set
of 40 patients and a test set of 121 patients. The manual delineations in the training set were parameterized and from this
parameter set a principle component analysis (PCA) were performed to extract a priori information regarding shape change
and motion during the cardiac cycle for the aorta ascendens. The proposed algorithm is an active contour model initialized by
a manual delineation in one timeframe. The active contour deformations are guided by vessel probability maps calculated by
a statistical image classification algorithm (expectation maximization). Every third deformation is followed by a projection
onto a subset of linearly independent components of the a priori dataset. This procedure is repeated 10 times.
Validation was performed by comparing automated delineations with manual delineations of the aorta ascendens in the test
set consisting of the 121 remaining patients. All automatic segmentations were initiated with the manual delineation in the
first timeframe. Calculated stroke volume and a similarity measure (Dice coefficient) were used as performance measure.
The Dice coefficient ranges from 0.0 to 1.0, where 1.0 corresponds to perfect agreement between manual and automatic
delineations. Inter observer variability for manual observers was analysed for 20 patients in the previous study [1].
3. Results
The result for stroke volume is shown in Figure 1. The stroke volume from the automated method agreed well with manual
delineations, with a correlation coefficient of r2 = 0.97. Bias between automated and manual delineation was -1.9 ± 3.2 ml, or
-2.2 ± 4.6 % of the stroke volume. This should be compared to an inter observer variability of 3 ± 4 % [1]. The mean Dice
coefficient was 0.93 ± 0.02 (range 0.83-0.97).
4. Conclusions
In conclusion, the proposed method performs vessel segmentation with bias and variability comparable to gold standard
manual delineations.
References
[1]. M. Carlsson, R. Andersson, K. Markenroth, K. Steding, H. Mosen, F. Stahlberg, B Ekmehag, H. Arheden. "Cardiac
output and cardiac index measured with cardiovascular magnetic resonance in healthy subjects, elite athletes and patients
with congestive heart failure." Journal of Cardiovascular Magnetic Resonance, 14(51), 2012.
Figure 1: Left panel shows a scatter plot of automatically measured stroke volume, and gold standard (manual delineation).
The solid line indicates line of identity. Right panel shows the Bland-Altman plot of manual and automated delineation. The
dashed lines indicate ±2SD and the solid line indicates bias between the two methods.
39
Sammanfattningar
Patientsäkerhet & utbildning
Session 2D
Moderatorer:
40
40
2D1
Patient Safety: A Measure on Reporting System and Accident Investigation in Bangladesh
1
Md Shafiqur Rahman Jabin1, Mohammad Saiful Islam2 ,Mannan Mridha1
KTH, School of Health and Technology, Stockholm, Sweden. 2BSM Medical University, Dhaka, Bangladesh
1
Introduction
Bangladesh, like many other developing countries in the world, has inadequate access to safe health care not only in the rural
areas but also in different hospitals, especially in public ones in the cities. Every year, a very large number of people die or
get severely injured due to preventable adverse events associated with medical devices, medication error, unsafe blood
collection or transfusion, surgery, anesthesia and obstetric trauma that occur during treatment or due to the negligence of the
healthcare personnel or incompetent practices used in regard to the safety of the patients. As a result, patients in Bangladesh
lose their trust in both public and private hospitals due to poor quality and unsafe care that cause a growing outflow of
Bangladeshi patients to the hospitals of neighboring countries. Therefore, to promote patient safety, effective research studies
are required to help healthcare professionals and policy makers to understand the complex causes that lead to unsafe care.
2
Method
The aims of the project were to describe safety issues in selected safety-healthcare domain, lining up a measure on reporting
systems of three private and three public hospitals and to make recommendations leading to the development or local
adaptation of appropriate, affordable and effective solutions. The method included three different case studies. The first case
study (CS1) compared rural healthcare services [1] in a village (Magura) with that of in the available in the city (Dhaka) The
second case study (CS2) included a measure on safety case practices in six different public and private hospitals in Dhaka. It
surveyed safety case practices, for example, suspected adverse drug reaction and its reporting system, systematic review of
complex Diagnostic Laboratory and Intensive Care Unit (ICU) set up, infection control, medical devices domain and their
respective reporting system on adverse events. Thus, this study assessed the main drivers and barriers and made
recommendations for the adoption of safety cases and general reporting system in healthcare sectors [2]. Our third case study
(CS3) involved a measure on accident investigation of a particular case in order to understand and interlink with first two
case studies. Preparation of a protocol was developed initially in consultation with local experts. Information and data were
collected through interviews firstly, by visiting the village doctors at their private chambers in Magura district and later from
the doctors, laboratory chief, technicians and nurses in different private and public hospitals. Data evaluation and
management were performed using written notes, cross tabular analysis, SPSS for all three case studies. However, the
accident investigation was analyzed using RCA-MTO method and FRAM [3]. Recommendations from both these methods
were generated and compared with each other.
3
Results
Our project work have shown promising results indicating that the entire method has the ability to measure the extent of harm
caused during healthcare delivery and subsequently prevent them and thus improve the patient safety. CS1 indicated that the
most rural health care providers are neither well educated not adequately trained. Therefore, severe health hazards are
common practice. Incorrect diagnosis due to lack of medical devices, unethical practices of prescribing inappropriate and
unnecessary drugs by the village doctors often cause severe harm to the patients. This can be avoided by training the underskilled village doctors, and some positive impacts of e-Health activities in this area have been identified. CS2 has pointed out
that the limitations of infrastructure, technology, resources and management including reporting, feedback and training cause
greater risks of patient harm resulting in breakdown of entire system of patient care. It also showed that there was a complete
absence of safety management and reporting system of medical adverse events especially in the public hospitals. CS3 helped
to find out how adverse events occur during treatment; either due to lack of communication between surgical team members
or informal methods used by the healthcare personnel.
4
Discussion
Study of regulatory process was not included in the main scope of this work. However, during the course of the study, it was
identified that, government regulations to report accidents are essential to ensure reporting of adverse events. Moreover, all
the field studies held as part of this project brought together academicians and experts in healthcare safety along with
clinicians, patient safety managers, laboratory chiefs and regulators. The dialogue resulted in bringing new insights and
concerns to identify enablers and barriers to the useful adoption of safety methods in healthcare. Thus, these attempts and
dialogues should continue in order to ensure that the proposed solutions remain clinically relevant and practicable to the
current critical healthcare safety conditions in Bangladesh. Patients safety study is a new field in Bangladesh and there
remains a considerable amount of work to be done, such as, awareness has to be developed, organizational structure needs to
be enhanced, rules for safe use of medical devices have be followed, and a well- structured reporting system in public
hospitals has be introduced involving patients and their families too.
Acknowledgements: The study was partly supported by Swedish Research Links and MFS
References
[1] Shehrin S Mahmoud et al, Are Village doctors in Bangladesh a curse or a blessing? (research article), Social and
Behavioral Science Unit, Public Health Sciences Division, BMC International h Health and Human Rights, 2010.
[2] WHO. Draft Guidelines for Adverse Event Reporting System and Learning System, WHO/EIP/SPO/QPS/05.3
[3] Helen Alm, Woltjer R, Patient safety Investigation through the lens of FRAM; Human Factors: A system view of human,
technology and organization, ISBN 978-90-423-0395-9.
41
2D2
PATIENT SAFETY REGARDING MEDICAL DEVICES AT ICUS IN BANGLADESH
Tonima Afroze1, Mia I. Palmqvist1, Dr. Mohammad S. Islam2, Dr. Mannan Mridha1 and Dr Björn -Erik Erlandsson1
1
School of Technology and Health, Kungliga Tekniska Högskolan, Stockholm, Sweden
2
BSM Medical University, Dhaka, Bangladesh
1
Introduction:
Healthcare errors are a persistent threat to patient safety. Up to 98,000 patients die because of human error in U.S. hospitals
each year. Critical care is one of the areas in which human errors occur most frequently. Error rate was 1.7 per patient per
day in the intensive care unit (ICU), 45.8 percent of ICU were associated with an adverse event, 45 percent of all error were
preventable [1]. To prevent errors made at the ICU, we need to know why they arise. Intensive care units look after patients
whose conditions are life-threatening and need constant, close monitoring and support from equipment and medication to
keep normal body functions going. They have higher levels of skilled staff, specialist monitoring and treatment equipment.
Patients with critical illness suffer from failure of one or more of their systems such as the heart, lung or kidneys. Heart
attack, stroke, poisoning, pneumonia, surgical complications, major trauma as a result of road traffic accidents, a fall, burns,
an industrial accident or violence are all examples of critical illnesses. Infections are a common cause of ICU admission. ICU
patient is weakened and has lessened ability to fight off infections, and is too sick to protect from errors. Managing and
learning from error is our priority, and can be achieved with an understanding of the roots, nature and consequences of error.
Such an understanding can improve management activities and will lead to fewer care-related injuries and deaths and cost
effectiveness, which favors the patient, patient’s family, the hospital and society.
2
Aim of Study: This study aimed to
a) Compare the conditions of medical devices at ICUs in private and public hospitals, b) Increase understanding of errors, risks
and accidents related to medical devices;, c) Study reporting systems and communication between staff at ICUs, d) Find ways to
minimize hazards related to medical equipment to ensure effective and safe use of devices.
3
Method:
Data was collected through interviews during field visits to three government and three private hospitals in Dhaka, Bangladesh.
We interviewed the chiefs of the ICUs, physicians, nurses and technicians working at the ICUs, to find Human Error, human
factors leading to accidents and to prepare a list of error-producing conditions (EPCs) that can affect both performance and the
potential to increase the probability of error when a specific task is performed in the presence of these conditions.
4
Results:
We found that that the nurses at the public hospitals identified many risk factors such as, work environment, workload,
communication within their team, physical and mental well-being, and lack of knowledge. Organizational factors, inadequate
training lack of competent technical support were also mentioned as the causes of poor performances. Public hospitals are very
cheap whereas the private ones are out of reach for the majority of the population. Public hospitals offer extremely low quality
services due to the limited resources. Pronounced differences could also be observed in maintenance and calibration of medical
equipment, further education of staff, working environment and infection control. The reporting systems at both types of
hospitals were inadequate, and the equipment procurement process was lengthy at all hospitals. Only the private hospitals had a
Biomedical Engineering department, which led to better maintenance and calibration of devices. Access to disposable items was
limited at several hospitals. It was found that reporting systems for adverse events and communication about patients’ conditions
between coworkers was weak at all hospitals. A hierarchical medical team, an absence of self-awareness of errors, and absence of
medical technicians makes patient care situation very risky
5
Discussion:
Government hospitals are almost free, but the quality of care is extremely poor due to overload. The poor patients seldom
question about the quality or safety aspects. Shortage of technical resources, inadequate skilled workers, poor hygienic conditions
and the doctors’ conflict of interests due to their private practices at the private hospitals are some of the causes of adverse
events. In order to improve the work in the ICU, a number of suggestions have been proposed. An in-house clinical engineering
units at all large hospitals will result in better procurement system, proper use, management and maintenance, and adaptation of
medical equipment. Educational and organizational improvements should be made, in particular, education in infection control,
patient safety and user safety for health care workers. ICT can substantially improve the safety of medical care by structuring
actions, catching errors, and bringing evidence-based, patient-centered decision support to the point of care to allow necessary
customization [2]. Such tools can also be used for spreading information on the use, management and solutions to common
technical problems related to specific devices. An internet forum for consultation on these subjects can be constructed for
technicians. Based on the present findings, it appears that questionnaires—in addition to observational approaches used can be
useful to identify errors at the ICU. Further study is being conducted to increase our understanding of device-related human error
in the ICU. This is an important step toward the goal of reducing hazards and improving patient safety.
Acknowledgements: The study was partly supported by Swedish Research Links and Minor Field Studies
References:
[1] Error Producing Conditions in the Intensive Care Unit by Frank A. Drews, PhD, et al. Kohn LT, Corrigan JM, Donaldson
MS editors. To err is human: Building a safer health system. Washington, DC: National Academies Press; 2000.
[2] Bates DW, Gawande AA. Patient safety: Improving safety with information technology. N Engl J Med. 2003;348:2526–
2534. [PubMed]
42
2D3
2D4
Renhet i operationsrum – En presentation av SIS-TS 39:2012
1
1
Philip De Geer
Swedish Standards Institute
1. Introduktion
SIS tekniska specifikation Mikrobiologisk renhet i operationsrum - Förebyggande av luftburen smitta - Vägledning och
grundläggande krav (SIS/TS 39:2012) har nu varit tillgänglig sedan augusti 2012. Dokumentet har väckt stort intresse och
varit föremål för många frågor och kommentarer.
2. Metod
Den tekniska specifikationen ger funktionskrav samt vägledning till teknisk utformning av ventilation och anger metoder för
utvärdering av ventilationens förmåga att avlägsna mikroorganismer från luften. Samspelet mellan kläder och ventilation
beskrivs också.
3. Resultat
Avsikten med denna tekniska specifikation är att ge vägledning för hur luftburen smitta till operationssår och
medicintekniska produkter kan minimeras i operationsrum och angränsande lokaler. Syftet är att förebygga postoperativa
infektioner förorsakade av luftburna mikroorganismer.
Andra viktiga åtgärder för renhet i operationsrum är iordningsställande av rummet före och avveckling efter operation,
arbetssätt och flöden för patient och personal. Dessa områden belyses men ligger utanför den egentliga ramen för den
tekniska specifikationen.
43
Bättre vård med beslutsstödsystem kopplade till register 2D4
Peter Funk, Professor, Intelligenta system, Mälardalens Högskola, Västerås, [email protected], 021 10 31 53 Ett exempel på beslutsstödsystem för bättre individuell smärtlindring efter
operationer är PAIN OUT, ett webbaserat beslutsstödsystem framtaget för
bättre postoperativ vård. Vid de cirka 40 miljoner
operationer
som
varje
år
genomförs i Europa upplever mer
än hälften av patienterna höga
smärtnivåer, något som ofta
förlänger tillfrisknandet. I EUprojektet PAIN OUT är målet att
förbättra
behandlingen
av
patienter
med
smärta
efter
operationer för vilket vi utvecklat ett webbaserade kliniska beslutsstödsystem. – En bättre smärtbehandling förkortar tillfrisknandet och är ett moraliskt ansvar.
Standardmetoder passar kanske 70 procent av alla, men ger samtidigt 30 procent av
patienterna en mindre optimal behandling, där kommer PAIN OUT in. Beslutsstödsystemet
använder fallbaserat resonerande, bygger på över 13 års forskning inom självlärande
algoritmer och fallbaserat resonerande och utgår från patienten. Systemet identifierar
liknande patienter i de cirka 37 000 patientjournaler från nio olika länder som finns i
systemet och drar slutsatser från dessa. Läkarna kan fatta beslut på individuell basis, med
bättre underlag, genom att se uppgifterna om de avidentifierade patienterna i registret som
listar uppgifter som ålder, kön, vikt, sjukdomshistoria och annat som kan vara av vikt för
smärtbehandlingen. I journalerna inom projektet har patienterna själva bedömt sin smärta
före, under och efter operationerna. Beslutsstödsystemet finns på en läsplatta som
specialistläkarna och kliniker kan ta med sig ut till patienterna. Där kan beslutsstödsystemet
identifiera liknande patienters journaler och dra slutsatser från dessa. Det gör det möjligt för
läkarna att få kunskap just i det ögonblick de behöver den, något som de som testat systemet
hittills tyckt varit mycket positivt. Beslutsstödsystemet öppnar helt nya möjligheter för de kliniska specialisterna och läkarna. I
dag samlas allt större volymer data in inom vården. I framtiden kommer den insamlade
informationen bli grunden i fallbaserade beslutsstödsystem och kommer därmed till direkt
och omedelbar nytta och värde både lokalt, nationellt och globalt. Nu blir nästa steg att ta
forskningsprototypen mot en produkt tillgänglig för klinisk användning. Målet är att alla
sjukhus i Europa ska använda systemet inom tre till sex år. Om PAIN-OUT: PAIN-OUT är ett forskningsprojekt med mål att förbättra hanteringen av
smärta efter operationer i Europa. Projektet finansierades inom EU:s sjunde ramprogram
med närmare tre miljoner euro 2010-2012. Ett konsortium har nu bildats för att få ut
resultaten till sjukhusen och över 100 sjukhus i Europa har anslutit sig PAIN OUT. Peter
Funk och Mobyen Ahmed ansvarar för vidareutvecklingen av beslutsstödsystemet. 16 sjukhus
och kliniska forskningscentra från Spanien, Sverige, Tyskland, Frankrike, England, Italien,
Schweiz och Rumänien samt många världsledande experter har aktivt deltagit i projektet.
www.pain-out.eu
44
2D5
INTEGRATION AV MEDICINTEKNISK GRUNDUTBILDNING I VÅRDEN
Sjoerd Haasl och Bertil Guve
Centrum för Teknik i Medicin och Hälsa, KTH/KI/SLL, Stockholm
1. Sammanfattning
Clinical Innovation Fellowships är en flerårig satsning där tvärdisciplinära och högkvalificerade team går in i sjukvården för
att identifiera behov och utifrån dessa behov både ta fram förbättringar till sin respektive värdklinik och en uppfinning samt
affärsplan som kan ligga till grund för ett startupföretag inom medicinteknik. Detta abstract beskriver programmets
interaktion och synergier med grundutbildningen på KTH och andra icke-medicinska läroverk.
2. Bakgrund: om Clinical Innovation Fellowships
Clinical Innovation Fellowships finansieras av KTH, KI och SLL tillsammans med Erling Perssons stiftelse. Satsningen är
inspirerad av ett innovationsprogram för medtech på Stanford som heter BioDesign och som har varit väldigt framgångsrik
sedan dess start 2001. CTMH startade med Clinical Innovation Fellowships 2010 och varje år i oktober tar vi in två
tvärdisciplinära team som placeras på var sin värdklinik för att på ett strukturerat och systematiskt sätt ta fram kliniska
innovationer utifrån kliniska behov. Teamen består av tre till fyra högkvalificerade individer (3-10 år yrkeslivserfarenhet)
med kompetenser inom medicin, management, teknik och design som jobbar heltid i åtta månader.
3. Programmets mål
1. Huvudmålet är långsiktigt: vi vill skapa ett aktivt kluster inom klinisk innovation i Stockholm. Vi vill ta vara på
förutsättningarna som KI, KTH, SLL och näringslivet inom medicinteknik i regionen ger genom ett nätverk av kliniker,
entreprenörer och forskare med ett intresse för medicinteknisk innovation där Fellows utgör centrala noder.
2. Att utbilda framtidens ledare inom klinisk innovation: fellows är innovatörer med en djup förståelse för den kliniska
miljön och medtechindustrin
3. Att skapa förbättringar som direkt gynnar värdklinikerna samt innovationer som leder till nya medicintekniska
företag i Stockholm
4. Upplägg: åtta månader
Tidsschemat för de åtta månaderna speglar designmetoden framtagen av Stanfords Biodesign Fellowships och tillämpas även
i Dublin, Barcelona, Singapore och Stockholm:
vecka 1-2: En intensiv utbildning i Biodesigns innovationsprocess och i värdklinikens verksamhet, både medicinsk,
organisatorisk och finansiell. Utbildningen fortsätter även efter v2 i form av ett seminarium varje vecka kring relevanta
ämnen, såsom hälsoekonomi, offentlig upphandling, CE-märkning, affärsplan osv.
vecka 3-7: En klinikvistelse där kandidaterna har full tillgång till hela verksamheten och observerar genom att följa och
intervjua läkare, sköterskor och patienter
vecka 8-10: En formulering och kvantifiering av kliniska behov utifrån observationerna. Behoven kvantifieras utan att de
tänker på specifika lösningar: hur mycket lidande skulle man slippa om behovet löstes? Hur många liv skulle sparas? Hur
mycket arbetstid sparas? Hur mycket skulle en klinik vara villig att betala för att lösa behovet? Är detta ett behov som bara
finns på denna klinik, eller även på andra ställen? Osv.
vecka 11-34: Lösningsfasen, framtagning av tre leverabler:
a. en rapport till värdkliniken med behov och lösningsförslag
b. tre examensarbeten som löser kliniklokala behov, dvs behov som har stor effekt för värdkliniken, men inte nödvändigtvis
behöver ligga till grund för ett företag
c. en affärsplan för kommersialisering av en medicinteknisk innovation
Vid framgångsrik avslutning av programmet diplomeras deltagarna med titeln Clinical Innovation Fellow vid KTH och KI.
5. Synergier med grundutbildning
Under de första tre åren har programmet visat sig leda till stora synergier med grundutbildningen. Utgående från behov som
de har identifierat under sin klinikvistelse har Fellows handlett:
1. Examensarbeten inom medicinteknikutbildningen på KTH, både på kandidatnivå (22 studenter) som på masternivå (3
studenter)
2. Examensarbeten inom andra områden (Industriell ekonomi, Företagsekonomi, ICT, Matematik) på KTH, Lunds
Universitet och Stockholms Universitet, även här på kandidat och masternivå (2 resp 7 studenter)
3. Projektarbeten inom kursen Produktutveckling inom den biomedicinska industrin, på Unit of Bioentrepreneurship på
Karolinska Institutet: 42 studenter.
Förutom dessa projekt- och examensarbeten involveras fellows vid olika tillfällen i grundutbildningar, både som föreläsare
(på KTH, Konstfack) och som sakexperter kring behov.
6. Slutsatser
Studenterna får, tack vare dessa behov samt genom fellowshandledningen och de kontaktytor som fellows har mot vården, en
ovärderlig relevans till den värld som de utbildas för att verka i. Samtidigt bidrar studenternas arbete direkt till de
förbättringar som fellows har som uppdrag att leverera till sin värdklinik. För representanterna från sjukvården är kontakten
med projekt- och examensarbetare oftast ett nytt arbetssätt. Värdklinikerna har vid upprepade tillfällen uttryckt en stor
uppskattning för det arbete som studenterna utför under ledning av fellows.
45
MEDICINTEKNISKA INGENJÖRER
1
1
2D6
2
Anna Hagman , Karin Nilsson
2
Kungliga Tekniska Högskolan, Stockholm, Sweden. Kungliga Tekniska Högskolan, Stockholm, Sweden
1. Bakgrund
Allt fler lever längre, allt fler blir sjuka, allt fler önskar en ökad livskvalitet. Allt fler söker en möjlighet för sjuka att bli
friska, och för redan friska att må ännu bättre. Framtidens vision om en högre välfärd gör hälsa och välbefinnande för alla
individer till samhällets viktigaste och största utmaning.
Med en djup kunskap inom både teknik och medicin, ligger medicintekniska ingenjörer i framkant med en inbyggd vision om
att öka graden av medicinsk innovation – medicinsk innovation som skall leda till mer effektiva hjälpmedel och därmed en
högre välfärd. Hos medicintekniska ingenjörer finns all den kunskap som behövs för att underhålla och utveckla den allt mer
teknologiskt avancerade vården.
Detta samspel av medicinsk och teknisk kunskap, skulle genom en interaktion mellan näringsliv och studenter skapa en
plattform för framtiden.
2. Utbildning
Kungliga Tekniska Högskolan tillhandahåller två unika program vilka är inriktade mot medicinsk teknik – en treårig
högskoleingenjörsutbildning samt en femårig civilingenjörsutbildning. Civilingenjörsutbildningen var den första i Sverige,
och startade år 2008. Utbildningarna skiljer sig på så sätt att högskoleingenjörsutbildningen är mer praktiskt inriktad, medan
civilingenjörsutbildningen är mer teoretisk. Vad de två utbildningarna har gemensamt är den medicintekniska inriktningen.
Vid sidan av klassiskt tekniska kurser som matematik, fysik, programmering och reglerteknik, läses kurser som fysiologi,
bioteknik, medicinska bildgivande system samt kvalitet och regelverk inom medicinsk teknik. Detta lägger grunden för ett
tvärvetenskapligt tänkande, med en inblick i både människa och samhälle. Det skapar en bred kompetens med mycket goda
gränsöverskridande kunskaper inom medicin och teknik. Det utvecklar en stark analytisk förmåga – en förmåga att analysera
och lösa problem genom innovativt tänkande.
3. Framtid
En utbildad medicinteknisk ingenjör har stor kompetens att arbeta inom såväl sjukhusbranschen som vid företag som
utvecklar, tillhandahåller eller inriktar sig mot medicinteknisk apparatur. En medicinteknisk ingenjör kan arbeta med
forskning och utveckling, med undervisning eller entreprenörskap. En medicinteknisk ingenjör kan vara företagsledare,
projektledare, produktutvecklare eller konsult. En medicinteknisk ingenjör är en tillgång i alla företag eller projekt som har
en samverkan mellan människa och teknik.
Utbildningen är ännu ung och namnet har inte hunnit etableras än, varför många företag inte känner till de kommande
ingenjörerna. Att behovet av dessa ingenjörer är stort är dock ett faktum, att sprida studenternas namn och kunskap likaså.
Programmet är skräddarsytt efter framtidens behov och önskemål, vilket ger studenterna en exklusiv spetskunskap.
Medicintekniska ingenjörer är unika.
Genom utbyten som examensarbeten, praktikplatser, sommarjobb eller företagsevenemang ökar interaktionen mellan
näringsliv och studenter. Genom att inleda en diskussion och ett samarbete, byggs en bro mellan behov och kunskap - en
gemensam väg som leder mot en friskare framtid.
46
Sammanfattningar
Sensorer och implantat
Session 4D
Moderator: Fernando Seoane
47
47
4D1
A micromachined millimeter-wave medical sensor for skin-cancer diagnosis
Fritzi Töpfer1, Sergey Dudorov1, Dragos Dancila2, Robin Augustine2, Xin Hu2, Lennart Emtestam3, Kari Gustafsson4, Lars Tenerz5,
Anders Rydberg2 and Joachim Oberhammer1
1
2
KTH Royal Institute of Technology, Uppsala University, 3Karolinska Institutet, 4ADAKT AB, 5OPTIGA AB
1. Medical motivation
Skin cancer is the most common cancer in the age group of 15-45 years. Incidents are increasing by an average of 3-6% per
year since the 1960s, and melanoma are among the most deadliest cancer types with 15-20% mortality. In Sweden, there are
about 2500 melanoma and 1200 precursors diagnosed per year, resulting in almost 500 deaths in 2011. A huge screening
effort is needed to find skin cancer: about 50-250 screenings have to be done for finding a single melanoma. There is no
established sensor technology available, diagnosis is so far been done by highly-trained dermatologists using dermatoscopes,
and after extraction verified by histological analysis. In Sweden alone, about 100 000 preventive skin surgeries are performed
every year, most of which are unnecessary and could be avoided if a diagnosis tool with high sensitivity/specificity would be
available. Specialized dermatology departments are increasingly becoming a bottleneck.
2. Method: a drastically miniaturized, 100-GHz millimeter-wave sensor for skin-cancer diagnosis
Electromagnetic waves at microwave frequencies are known to be able to distinguish healthy from tumour cells, as energy
absorption above 1 GHz is significantly higher due to increased free and bound water content of fast and uncontrolled
growing tissue [1]. The discrimination of healthy/cancer tissue by microwaves has also been shown for skin tumours, incl.
BCC [2] and melanoma [3]. Macroscopic microwave sensors, available up to 40 GHz, have a too large interaction volume
and are therefore not suitable for analysing shallow and inhomogeneous skin cancer tissue at an early stage.
This paper presents the results of a micromachined millimeter-wave probe operating at 100 GHz, which has a probe tip with
only 0.9% of the contact area of a conventional microwave probe and with a penetration depth matched to shallow skin
cancer tissue layers, and uniquely combines high sensitivity and high resolution. Two different probe designs, a broadband
design by KTH and a resonance concept by UU, have been implemented by micromachining and characterized.
3. Results: technical verification, first measurements on skin
Probe prototype 1 (KTH design) has successfully been technically verified, resulting in a responsivity of S11/εr=0.47dB in the
permittivity range of cancer/healthy tissue at 100GHz, a reproducibility better than 1.4% (1σ), a long-term stability better
than 0.6% (1σ) for 8h, and a lateral scanning resolution of about 100μm for a 600x300μm2 probe tip. First tests on human
skin revealed that the probe can clearly distinguish skin tissue on different positions of the body (back of hand, palm, arm),
can detect skin burns and can monitor the healing process of skin burns (discrimination between burnt skin, newly grown
skin, normal skin), and can distinguish benign skin neoplasms from normal skin and subdermal (junctional) nevi.
Probe prototype 2 (UU design) is a resonant probe design which has been tested on phantom materials composed of agar,
polyethylene powder and TX-15. The probe can successfully distinguish 50%, 75%, and 100% phantom materials.
4. Conclusions, outlook, acknowledgements
We presented a new type of microwave wave medical sensor, enabled by micromachining. The probes were optimized for
skin cancer, and provide a unique responsivity/resolution performance as compared to conventional microwave probes. The
sensor prototypes have been successfully technically characterized and measurements on different skin types and skin
anomalies have clearly verified the sensor function. Currently, an application for ethical approval is being filed for continuing
the work towards evaluating cancer tissue. The VINNOVA Framtidens Hälsa programme is acknowledged for funding.
References
[1] Mariya Lazebnik et al., Phys. Med. Biol. 52 (2007) 6093–6115.
[2] R. M. Woodwardet al. , J. Invest. Dermatol., vol. 120, pp. 72-78, 2003.
[3] A. Ito et al., Cancer Sci., vol 94, no. 3, pp. 308-313, Mar. 2003.
(a)
(c)
(d)
(e)
(b)
Figure 1: Mmicromachined microwave skin-cancer sensor prototypes: (a) broadband sensor, (b) resonant type sensor;
(c) responsivity analysis; (d) measurements on skin, discrimination of burnt/new-grown/normal skin; (e) measurements on
skin, benign skin neoplasm/subdermal mole/normal skin.
48
4D2
INBYGGDA SENSORSYSTEM FÖR HÄLSA - FORSKNINGSPROFILEN ESS-H
Maria Lindén, Mats Björkman
Mälardalens högskola, Sverige
1. Introduktion
Embedded Sensor Systems for Health (ESS-H), är en 6-årig forskningsprofil inom inbyggda system för hälsa. Profilens
hemvist är Mälardalens högskola, Akademin för Innovation, Design och Teknik. Totalt satsar KK-stiftelsen, MDH och
företagen 84 miljoner kronor på forskningsprofilen. KKS står för 36 miljoner kronor, företagen för 30 miljoner kronor och
MDH för 18 miljoner kronor. Inom ESS-H ska högskolan tillsammans med nio företag samt kommuner och landsting
utveckla sensorsystem som främjar hälsa. Sensorsystemen ska monitorera och följa hälsotillståndet hos äldre i hemmiljö, men
även monitorera yrkesförare och maskinoperatörer och därigenom åstadkomma säkrare arbetsmiljö.
Profilen utgår från ett systemperspektiv och kombinerar multidisciplinära kompetenser. Såväl hårdvaru- som
mjukvaruaspekter inkluderas. Målet med ESS-H är att akademi och industri, tillsammans med hälsovård, sjukvård och
vårdgivare ska finna nya tekniska lösningar för att främja hälsa speciellt inom två områden: i hemmet och på arbetsplatsen.,
2. Motivering
Hälso- och sjukvårdskostnaderna ökar i Sverige, liksom i resten av västvärlden. Den åldrande, multisjuka befolkningen står
för en stor del av dessa. Intelligenta, adaptiva system som kan monitorera och utvärdera hälsostatusen för dessa
patientgrupper är viktiga. Dessa kan bidra till monitorering, prevention och rehabilitering, t ex genom att följa individens
hälsotillstånd och tidigt kunna identifiera en försämrad hälsostatus och sätta in åtgärder.
En stor del av de arbetsplatsolyckor som inträffar sker i stressiga eller farliga miljöer. Användningen av intelligenta, adaptiva
system som monitorerar omgivningen och/eller fysiologiska parametrar kan bidra till att göra arbetsplatserna säkrare.
3. Kärnkompetenser och stödjande teknologier
Kärnkompetenserna inom ESS-H är Medicinsk sensorteknik, Medicinteknisk signalbehandling och Intelligent beslutsstöd.
Verifierbarhet och säkerhet är viktiga aspekter inom inbyggda sensorsystem för hälsoapplikationer. De stödjande
teknologierna utgörs av Mjukvarutestning och Säker trådlös kommunikation och utgör viktiga pusselbitar för att de inbyggda
sensorsystemen ska kunna tillämpas inom hälsodomänen.
Figur 1. Kärnkompetenserna inom ESS-H.
4. Forskningsutmaningar
Inom ESS-H har tre huvudutmaningar identifierats:1) Insamling av tillförlitliga fysiologiska data, 2) Personlig biofeedback
och 3) Tillförlitliga distribuerade beslutsstödssystem.
Var och en av dessa forskningsutmaningar kräver multidisciplinär forskning. Forskningsutmaningarna adresseras i ett antal
samverkande forskningsprojekt där varje delprojekt kombinerar samtliga kompetenserna inom ESS-H, både
forskningskompetensen inom kärn- och stödteknologierna, men även expertis från partnerföretagen.
5. Delprojekt
Forskningen inom profilen är systemorienterade och samtliga delprojekt adresserar det tre huvudutmaningarna inom
ESS-H. Delprojekten är inledningsvis:
• Sensorsystem för hälsomonitorering hemma
• Sensorsystem för hälsa på jobbet (speciellt farliga yrken)
• Infrastruktur för fysiologisk databehandling (inklusive kommunikation)
Det kommer att bli stora synergieffekter och samarbeten även mellan delprojekten.
49
49
4D3
PIEZOELEKTRISK TEXTIL FIBER FÖR MEDICINSKA APPLIKATIONER
Erik Nilsson1,2, Karin Rundqvist3, Anja Lund2,3, Bengt Hagstöm1,2
Swerea IVF, Textiles and Plastics Department, Box 104, SE-431 22 Mölndal, Sweden
2
Dept. Materials and Manufacturing Technology, Chalmers University of Technology,
SE-412 96 Göteborg, Sweden
3
The Swedish School of Textiles, University of Borås, SE-501 90 Borås, Sweden
1
1. Introduktion
Övervakning av hjärtslag- och andningsljud är vanligt förekommande i vården och möjligt genom flera olika tekniker.
Elektrokardiografi (EKG) som är den mest exakta metoden, är också den vanligaste diagnostiska hjärtundersökningen i sjukvården. Men det finns tillfällen då man vill övervaka hjärtats frekvens över en längre tidsperiod, exempelvis vid längre
sjukhusvistelser eller hos personer med hjärtproblem som vårdas i hemmiljö och behöver observeras under en längre tid. Idén
med att integrera mätutrustningen i klädesplagget ökar patientens välbefinnande, mobilitet och integritet [1]. Något som
rimligtvis bör gynna läknings- och återhämtningsprocessen.
Inom det textila området har det nu utvecklats lösningar där sensorer integreras i klädesplagget. Genom att använda
metalltrådar insydda i plagget kan de elektriska signalerna från hjärtat registreras [2]. Alternativt kan de mekaniska rörelserna
som uppstår vid andning och hjärtats slag övervakas med piezoelektriska sensorer. Detta kan exempelvis ske genom att ett
plåster med en piezoelektrisk filmsensor fästs på bröstet [3] eller att en sensor spänns fast med kardborreband på fingret [4].
Ingen av dessa lösningar är varken praktiska eller komfortabla att använda under en längre tid. I denna studie visar vi att det
går att skapa en sensor på fibernivå som har egenskaper likvärdiga med en kommersiell textilfiber och därmed inte har
negativ påverkan på användarens komfort då sensorfibrerna inte skiljer sig från de övriga fibrerna i textilen.
2. Metod
Fibrerna är tillverkade genom smältspinning som är den vanligaste metoden att tillverka syntetiska fibrer. Fibrerna är av
bikomponent typ med en ledande kärna av kolkomposit omgiven av ett hölje av polyvinyldifluorid (PVDF), en polymer med
piezoelektriska egenskaper. Fibrerna har utvärderats som enstaka garn och vävda till en textil. Signalen från fibern registreras
mellan den inre elektroden och en yttre elektrod. Testerna är genomförda i både dragprovare och fastspända på kroppen för
att mäta hjärt- och andningsljud.
3. Resultat
Mätningar i dragprovare visar att fibrerna är mycket känsliga.
Töjningar på 0.07% ger upp till 4 V utsignal från PVDF fibrerna vid
en dynamisk belastning på 4 Hz. Fibrerna mäter endast transienta
förlopp och frekvensområdet beror på impedansen hos
mätutrustningen. För optimal prestanda måste utrustningen anpassas
för det aktuella mättillfället. Figur 1 visar hjärtslag och andning från
en stillasittande person. Mätningen är gjord genom att en textil klämts
mellan resårbandet på sport-BH och huden på en person som är
sittande. Mätningar har även utförts med ett band som spänts kring
bröstet på testpersonen.
Genom att använda ett elektriskt ledande garn som yttre elektrod har
ett nytt textilt sensor-koncept utvecklats. Testerna visade att
signalstyrkan från PVDF fibrerna påverkas av det ledande garnets
konduktivitet,
grovlek
(Tex)
och
vävens
konstruktion.
Bindningstypen som gav högst signalstyrka var twill, som ger god
draperbarhet och är mest flexibel av de testade bindningstyperna.
4. Slutsats och diskussion
Försöken visar att det är fullt möjligt att att mäta hjärtslag och
andning med sensorer integrerade på fibernivå. Genom att integrera
sensorer i klädesplagget så ökar patientens komfort. Detta möjliggör
övervakning av patienter i deras hemmiljö utan att det inskränker på
deras livskvalitet. (Det kan bli möjligt att övervaka patienter i deras
hemmiljö utan att det inskränker på livskvaliteten) För att få ut en
maximal signal så skall fibrerna vara löst bundna i textilen. För vidare
arbete behövs elektronik för datainsamling med ett tillhörande
gränssnitt mot fibrerna utvecklas.
Figur 1 a) Hjärtslag för en stillasittande person
som håller andan och b) både hjärtslag och
andning.
Referenser
[1] F.H. Wilhelm, W.T. Roth, M.A. Sackner, Behavior Modification, 27, 671-­‐91 (2003). [2] S. Choi, Z. Jiang, Sensors and Actuators A: Physical, 128, 317-­‐26(2006). [3] Y.-­‐Y. Chiu, W.-­‐Y. Lin, H.-­‐Y. Wang, S.-­‐B. Huang, M.-­‐H. Wu, Sensors and Actuators A: Physical, 189, 328-­‐34(2013). [4] Y. Chen, L. Wang, W.H. Ko, Sensors and Actuators A: Physical, 23, 879-­‐82(1990). 50
INTEGRATION OF POLYMER MICROFLUIDICS WITH SILICON PHOTONIC BIOSENSORS
BY ONE-STEP COMBINED PHOTOPATTERNING AND MOLDING OF OSTE
1,2
1
3
1
4D4
1
Carlos Errando-Herranz , Farizah Saharil , Albert Mola Romero , Niklas Sandström , Reza Zandi Shafagh ,
1
1
1
Wouter van der Wijngaart , Tommy Haraldsson , and Kristinn B. Gylfason
1
2
KTH Royal Institute of Technology, Stockholm, Sweden. UPV Polytechnic University of Valencia, Valencia, Spain,
3
University of Barcelona, Barcelona, Spain
1. Introduction
Silicon-based sensors have recently demonstrated good performance in terms of biological and chemical analyte detection.
Silicon-based photonic ring resonators [1], DNA sequencing devices [2], and nanowire sensors [3] are examples of high
performance silicon sensors, featuring low detection limits, high scalability, and mass production capability in dense arrays at
low cost. However, for chemical and biological applications, silicon sensor fabrication faces a bottleneck: the integration of
liquid sample handling. Here, we present a fast and simple integration of microfluidics onto silicon photonic sensors. By
taking advantage of the OSTE polymer [4], we photopattern and mold microfluidics in a single casting step, without squeezefilm formation. By enabling photopatterning of vias both for fluid connections and optical fiber probing, the necessary wafer
area is reduced, enabling fabrication of fluidics on the same scale as current silicon sensor arrays. We demonstrate
measurements using a silicon photonic refractive index sensor fabricated by this process.
2. Method
OSTE with a 70% thiol excess is poured in a PDMS mold, defining connectors, and then sandwiched between the PDMS and
a glass mask. The glass mask has chromium dots defining vias, and SU8 reliefs defining microchannels, thus acting both as a
mold and photolithography mask. After a UV-exposure time of 15 seconds, the casting process is finished by releasing and
developing the OSTE layer with butyl acetate during 30 seconds. Thereby, the unexposed parts dissolve, and the vias for
optical and fluidic connections are opened. By taking advantage of the excess thiol functional groups on the OSTE surface,
we then covalently bond the fluidic layer to an isocyanate functionalized silicon optical chip, in a reaction that takes 10
minutes.
3. Results and discussion
We obtain squeeze-film free vias, and leakage free bonding to flat glass and silicon, including microchannels defined by thin
and long walls with bond areas down to 0.12 x 10 mm2 (Fig. 1). Moreover, we demonstrate bonding to silicon photonic chips
with 220 nm thick protruding waveguides, and show optical measurements with a Mach-Zehnder interferometer based
refractive index sensor. The results show a shift in the interference wavelengths with the introduction of air, isopropanol and
ethanol into the fluidic channel (Fig. 2).
4. Conclusions
We have demonstrated a one-step microfluidic integration technique for silicon photonic waveguide based sensors with
surface grating couplers. We replace the prevalent microfluidic integration solution (PDMS) with one based on the OSTE
polymer, and thus, by combined lithography and molding, we enable the integration of photolithographed vias for optical
probing with grating couplers (Fig. 1). Moreover, dry bonding of OSTE to silanized silicon photonic chips overcomes the
limitations of PDMS in bonding to biofunctionalized surfaces. We show leakage free bonding of microfluidic layers to
patterned silicon, together with refractive index measurements using a grating coupled Mach-Zehnder interferometer sensor
chip, fabricated by these means (Fig 2).Our demonstration of a functional photonic sensor, packaged by a fast single-step
microfluidic layer integration extendable to wafer-level fabrication, illustrates that our novel approach has the potential to
accelerate the commercial uptake of silicon based biosensors..
References
[1] Rothberg, J. M. et al. Nature 475, 348-352 (2011).
[2] Zheng, G. et al. Nature Biotechnology 23, 1294-1301 (2005).
[3] Luchansky, M. S. et al. Analytical Chemistry 84, 793-821 (2011).
[4] Carlborg, C. F. et al. Lab on a Chip 11, 3136-3147 (2011).
Figure 1: The Mach-Zehnder interferometer chip.
51
Figure 2: Transmitted optical power through the sensor.
51
4D5
A NEW BONE CONDUCTION IMPLANT (BCI) SYSTEM USED IN A FIRST CLINICAL STUDY
1
Hamidreza Taghavi1, Bo Håkansson1, Sabine Reinfeldt1, Karl-Johan Fredén Jansson1, Måns Eeg-Olofsson2
Department of Signals and Systems, Chalmers University of Technology, Gothenburg, Sweden. 2 ENT Department, Sahlgrenska University
Hospital, Department of Otorhinolaryngology, University of Gothenburg, Gothenburg, Sweden
1. Introduction
Patients with conductive and mixed hearing loss can be rehabilitated by percutaneous bone-anchored hearing aids (BAHA).
Even though the BAHA has been successful and more than 100,000 patients have been implanted, the skin-penetrating
implant site needs life-long daily care and some skin complications may occur. A new Bone Conduction Implant (BCI)
system has been designed and developed as an alternative to the percutaneous BAHA and recently implanted for long-term
use in four patients. In a BCI the skin and subcutaneous tissue is kept intact and the sound is transmitted via an inductive link
[1,2].
2. Method
The study was done on four patients in the clinical study phase. Two patients had bilateral conductive loss and two had
unilateral conductive loss. The BCI consists of an externally worn sound processor and an implanted unit called the Bridging
Bone Conductor (BBC), which is permanently implanted in the mastoid portion of the temporal bone. The BBC contains a
transducer, a tuned demodulator and uses an inductive link for communication with the external sound processor similar to
cochlear implants, see Figure 1. The BCI sound processor has been implemented in a very efficient ultra-low power
Application Specific Integrated Circuit (ASIC) that optimizes the power and sound transmission through the inductive link.
The inductive link gain has been designed to be fairly robust for skin flap thickness variations of 2-8 mm. The output force
level and total harmonic distortion of the BCI devices were measured on Skull simulator in an acoustic measurement set-up.
To measure the efficiency of the BCI, the battery current consumption of the BCI was also measured based on American
National Standards Institute standards. In addition, a nasal sound pressure (NSP) measurement was used as an intraoperative
method to verify that the implant operates properly before closing the incision.
3. Results
It was found that the BCI can generate high enough output force for the candidate patients with unilateral and bilateral
conductive hearing loss. The output force level of the BCI measured on Skull simulator is fairly robust for skin flap thickness
range of 2-8 mm. It was found that the battery current consumption of the BCI is in a range that can be used with a single
hearing aid battery for 5-7 days based on patients’ use. Moreover, it was shown that the NSP measurement on the patients
was a proper method for verification of the implant functionality during surgery and in follow-up sessions.
4. Conclusion
The Bone Conduction Implant has been developed and implanted in four patients and the performance and verification
methods show that the implant performs as expected after surgery. The NSP will be used as the verification method during
coming BCI surgeries.
References
[1] Håkansson B, Reinfeldt S, Eeg Olofsson M, et al. A novel bone conduction implant (BCI): engineering aspects and preclinical studies. Int J Audiol 2010;49:203-215.
[2] Taghavi H, Håkansson B, Reinfeldt S. Analysis and Design of RF Power and Data Link Using Amplitude Modulation of
Class-E for a Novel Bone Conduction Implant. IEEE Trans. Biomed. Eng 2012;59:3050-59.
Figure 1: The BCI system with an implanted and capsuled transducer with a flat surface contact to the temporal bone. The
vibrations are received to the cochlea by means of bone conduction. (BEST: Balanced Electromagnetic Separation
Transducer)
52
4D6
BCI - NYTT HÖRSELIMPLANTAT SOM ERSÄTTER SKADAT MELLANÖRA
Sabine Reinfeldt1, Bo Håkansson1, Hamidreza Taghavi1, Karl-Johan Fredén Jansson1, Måns Eeg-Olofsson2
1
Chalmers Tekniska Högskola, Göteborg, Sweden. 2 Sahlgrenska Universitetssjukhuset, Göteborg, Sweden
1. Introduktion
Patienter med hörselskada i ytter- eller mellanörat rehabiliteras idag med den
benförankrade hörapparaten BAHA. Den har blivit framgångsrik med mer än
100 000 opererade patienter. Apparaten fästs i benet med en titanskruv och det
blir en hudgenomföring som kan ge upphov till komplikationer. Daglig vård av
huden krävs och det kan uppkomma hudinfektioner och skruven kan lossna. En
del patienter nekar till BAHA för att de inte vill ha ”en skruv som sticker ut ur
huvudet”.
Vi har utvecklat ett nytt benledningsimplantat (BCI), där huden hålls intakt. För
att implantatet ska passa i temporalbenet bakom örat, så har själva högtalaren
gjorts mindre och genom en speciell teknik så är den mer effektiv och ger
mindre distortion än vad BAHA-vibratorn gör. Visionen är dels att det nya
benledningsimplantatet löser problemen kopplade till den nuvarande
hudgenomföringen i BAHA och dels att BCI ska ge lika bra hörselrehabilitering
för patienten.
BCI-systemet består av en extern ljudprocessor och en implanterad enhet, inkluderande högtalaren som vibrerar för att ge en
hörselupplevelse. Signalen transmitteras induktivt från ljudprocessorn, som fästs med magnet mot implantatet genom huden.
[1,2]
2. Metod
För att utveckla BCI har ett antal prekliniska studier genomförts, och just nu genomförs en klinisk studie med 20 patienter,
vilken godkändes hösten 2012 av Läkemedelsverket och Regionala etikprövningsnämnden. I skrivande stund har fyra
patienter fått implantaten inopererade och två av dem har även fått den yttre ljudprocessorn, vilken man får efter fyra veckor.
Ett stort testbatteri genomförs på varje patient, både före och efter operationen. Innan operationen får patienten använda en
referenshörapparat, vilken är en BAHA som fästs med elastiskt band. Vid samtliga besök mäts hörtrösklar för toner och tal,
samt uppfattbarhet av tal i brus.
För att veta att implantatet fungerar innan operationssåret sys igen så stimuleras implantatet med en elektrisk signal och
ljudtrycket i näsan mäts. Detta har visat sig vara en bra metod för kontroll av implantatet och används också i
uppföljningsbesöken för att följa implantatets funktion över tid.
Själva högtalaren i implantatet sänks ner i benet ungefär 20 mm bakom hörselgången och ljudprocessorn sitter då ungefär 55
mm från hörselgången, vilket är den vanliga positionen för BAHA. Högtalaren fästs med en titantråd; alltså behövs ingen
skruv för BCI.
3. Resultat
Vi kommer att visa resultatet av de audiometriska mätningarna vi har gjort på de första patienterna. Vi har sett en definitiv
förbättring av hörseln med BCI, och att BCI är jämförbar med
referenshörapparaten.
Operationsproceduren har utvecklats och är säker och enkel för både patient och
kirurg. Implantatets placering planeras med hjälp av cone beam computed
tomography (CBCT) för att ge bäst möjliga individanpassning.
4. Diskussion
Resultaten visar att BCI ger lika bra hörsel som en BAHA gör och har den stora
fördelen att huden hålls intakt. Dessutom sitter den närmare huvudet och ger
därför inte lika mycket vindbrus. En tredje fördel är att högtalaren sitter längre
ifrån mikrofonen än vad den gör i BAHA, och därför ger den mycket mindre
återkoppling jämfört med BAHA, vilket medför att det är möjligt att använda
mössa med BCI.
Operationen är säker och enkel och det är möjligt att kontrollera implantatets funktion med näsljudtryck innan
operationssåret sys igen.
References
[1] Håkansson B, Reinfeldt S, Eeg Olofsson M, et al. A novel bone conduction implant (BCI): engineering aspects and preclinical studies. Int J Audiol 2010;49:203-215.
[2] Taghavi H, Håkansson B, Reinfeldt S. Analysis and Design of RF Power and Data Link Using Amplitude Modulation of
Class-E for a Novel Bone Conduction Implant. IEEE Trans. Biomed. Eng 2012;59:3050-59.
53
53
Sammanfattningar
Plenarföredrag
Session E
Moderator:
54
E2
NANOMEDICIN – EN (R)EVOLUTION FÖR FRAMTIDENS SJUKVÅRD?
Agneta Richter Dahlfors
Professor, Director, Swedish Medical Nanoscience Center,
Karolinska Institutet, Department of Neuroscience,
Stockholm, Sweden
Nanomedicin är ett forskningsområde som med stor sannolikhet kommer att revolutionera framtidens sjukvård. Bland annat
kommer vi att få se nya metoder för att ställa diagnos, nya behandlingsmetoder och effektivare terapier. Detta möjliggörs
genom tät samverkan mellan forskare inom nanoteknik och medicin.
Genom nanoteknik kan material skapas och kontrolleras på nanometernivå. Detta öppnar för helt nya sätt att integrera
material med nya funktioner i medicinska applikationer, eftersom materialens storlek är tusen gånger mindre än kroppens
celler.
Nanomedicinens utveckling ställer emellertid även krav på samhället i övrigt. Både politiker och allmänhet måste delta i
diskussion om hur vi i framtiden skall utnyttja de oändliga möjligheter som nanomedicin kommer att erbjuda – en viktig
debatt som redan initierats i andra länder.
55
Sammanfattningar
Regelverk och ekonomi
Session 2F
56
56
2F1
Hälsoekonomisk utvärdering av medicinteknik
-en permanent verksamhet på nationell nivå?
Malin Blixt
Tandvårds- och läkemedelsförmånsverket, Stockholm, Sweden
1. Bakgrund
Regeringen uppdrog i april 2012 åt Tandvårds- och läkemedelsförmånsverket, TLV att genomföra hälsoekonomiska
bedömningar av medicintekniska produkter. Verksamheten skulle bedrivas i form av en försöksverksamhet och omfatta minst
två medicintekniska produktgrupper. En av dessa grupper skulle utgöras av insulinpumpar. När det gäller dessa produkter
skulle uppdraget delredovisas senast den 30 april 2012. Redovisningen skulle utgöras av ett kunskapsunderlag i form av
hälsoekonomisk bedömning av insulinpumpar.
Uppdraget ska slutredovisas senast den 31 oktober 2013. Slutredovisningen ska bestå av dels kunskapsunderlag i form av
hälsoekonomiska bedömningar av de utvalda medicintekniska produktgrupperna, dels en bedömning av om
försöksverksamheten bör permanentas och hur den i så fall bör utformas.
Av uppdraget framgår att TLV ska samråda med sjukvårdshuvudmännen och berörda organisationer samt samverka med
berörda myndigheter beträffande arbetsformer och det material TLV ska använda vid bedömningarna samt hur myndigheten
ska få tillgång till detta. TLV ska även under uppdraget föra en dialog med hälso- och sjukvårdshuvudmännen för att anpassa
kunskapsunderlagen till behoven hos mottagarna av dessa underlag.
De hälsoekonomiska bedömningarna av medicintekniska produkter förväntas vara ett stöd för hälso- och
sjukvårdshuvudmännen vid kliniska beslut och vid upphandling av produkterna. De hälsoekonomiska bedömningarna
påverkar dock inte frågan om produkterna ska ingå i läkemedelsförmånerna eller inte.
TLV och branschorganisationerna för medicinteknik bör i utvecklingsarbetet föra en dialog om vilket material som ska
användas och hur myndigheten ska få tillgång till detta. En fråga som bör diskuteras är vilka priser som ska användas vid
bedömningen. Det är angeläget att systemet blir förutsebart för att medicinteknikföretagen ska kunna utveckla rutiner kring
framtagande av underlag, samt åtar sig att förse TLV med detta underlag. Regeringens bedömning är att hälsoekonomiska
bedömningar av medicintekniska produkter gagnar patienter och vården på flera sätt. Bedömningarna väntas bland annat
bidra till
- bättre underlag för kliniska beslut och upphandling av medicintekniska produkter,
- större transparens kring medicintekniska produkters kostnadseffektivitet och priser,
- bättre utnyttjande av existerande resurser för kunskapsutvärdering genom att bedömningarna görs av en nationell myndighet
och inte av alla huvudmännen, samt
- en mer kunskapsstyrd och likvärdig användning av medicintekniska produkter i hela landet.
2. Reslutat
TLV anser att uppdraget bör bli permanent och kommer i slutrapporten att lämna en fullständig bild av hur vi anser att en
permanent verksamhet bör utformas. TLV inledde med att göra en marknadsanalys av landsting och andra myndigheter, dels
för att se hur de hanterar medicinteknik, dels för att se om de har några prioriteringslistor, eller andra transparenta
urvalsprocesser.
Det är oklart precis hur mycket pengar medicintekniska produkter omsätter varje år då landstingens redovisning kan ske på
flera olika sätt. En kvalificerad uppskattning är att kostnaderna för medicintekniska produkter är drygt 20 miljarder kronor.
Olika landsting lägger olika mycket på medicintekniska produkter. Det är stor skillnad på hur prioriteringarna görs, en del
landsting utgår enbart från årets budget, vissa landsting tittar på hälsoekonomi, andra landsting lyssnar mer på enskilda
läkare.
Det finns ett väldigt stort intresse för detta regeringsuppdrag från både organisationer, privatpersoner, andra myndigheter och
bransch samt landsting. Projektgruppen har fått många inbjudningar att prata om projektet och många har uttryckt att det är
efterlängtat. Bland annat branschföreningen menar att det finns ett undertryckt behov.
Den 2 september kommer myndighetens förslag till slutrapport att läggas ut på www.tlv.se för synpunkter för alla som är
intresserade. På Medicinteknikdagarna kommer att redogöras för vilka överväganden som har gjorts, hur en permanent
verksamhet bör bedrivas, vilka implikationer det får för olika aktörer och förhoppningsvis kommer det då även att vara klart
om och i så fall när en permanent verksamhet startar upp i myndighetens regi.
57
2F2
ERFARENHETER AV IT-BEROENDE MEDICINTEKNISKA PRODUKTER I GENERELL
IT-STRATEGI OCH FÖRVALTNINGSMODELL
1
1
1
Robert Lorentsson , Roger Lampa , Morgan Andréasson
1
Sahlgrenska Universitetssjukhuset, Göteborg.
1. Introduktion
I Västra Götalandsregionen (VGR) har en IT-översyn [1] genomförts som bland annat innebär en ny IS/IT-strategi, ny
förvaltningsmodell (pm3) och ny styrmodell. Inom IT-översynsprojektet fanns delprojekt för IT-beroende MTP som beskrivs
här. VGR har tre huvuduppdrag: hälso- och sjukvård, främja tillväxt och hållbar utveckling samt kollektivtrafiken. Regionen
har ca 50 000 anställda varav 90 procent arbetar i hälso- och sjukvården. IT-organisationen är sedan flera år regional och
medarbetarna är lokaliserade utanför sjukhusen centraliserat till de större städerna i regionen.
En förstudie [2] som beskrev hur IT-beroende MTP hanterades innan IT-översynen genomfördes och resulterade i ett antal
förslag som låg till grund för genomförandeprojektet. Dessa förslag var bland andra:
- Förvaltningsobjekt som innehåller mycket MTP bemannas med både Förvaltningsledare MT och Förvaltningsledare
IT på utförarsidan som tillsammans bildar funktionen Förvaltningsledning teknik (till skillnad från andra objekt
som endast har Förvaltningsledare IT på utförarsidan)
- Beredningsprocessen för IT kompletteras med erforderliga aktiviteter och roller för att hantera införande av ITberoende MTP
- En roll införs på varje sjukhus som samordnar investeringar i IT-beroende MTP
- En regional processägare införs för riskhantering av IT-beroende MTP
- Verksamhetsnära IT-stöd införs
- Sjukhusens kravställnings- och beställningsfunktion gentemot IT-organisationen kompletteras med MT-kompetens
Ett genomförandeprojekt med förstudiens förslag håller på att genomföras och avslutas troligtvis under maj 2013.
2. Avrapportering
Ett av förvaltningsobjekten inom hälso- och sjukvård innehåller mycket IT-beroende MTP, rekrytering av förvaltningsledare
MT pågår.
Regional processägare för riskhantering av IT-beroende MTP ska tillsättas. Ett initialt uppdrag kommer att vara att
implementera tillhörande regional process för riskhantering av IT-beroende MTP med stöd av SS-EN 80001-1 [3].
Erfarenheter gjorda vid implementering av styr- och förvaltningsmodellen i VGR ur ett MT-perspektiv:
Majoriteten av de IT-beroende MTP som har med diagnostik och terapi att göra hamnade i samma
förvaltningsobjekt. Detta objekt har fler IT-komponenter än de andra förvaltningsobjekten.
Kravet på regional samsyn avseende IT-beroende MTP möjliggörs med hjälp av förvaltningsledare MT som har
informations-, kommunikations- och förankringsansvar mot sjukhusens MT-organisationer.
- Förslag att ett regionalt team för verksamhetsnära IT-stöd från IT-organisationen avseende IT-beroende MTP ska
etableras.
Referenser
[1] VGR, IT-översynen. (2011), IS/IT-strategi, RSK 1200-200, Västra Götalandsregionen: VGR.
[2] Andréasson, M. (2012), Förstudie: Nuläge avseende MTP/MIS relaterat till regionens nya IT-strategi,
http://tiny.cc/c81gkw.
[3] SEK TK 62. (2011). Riskhantering tillämpad på IT-nätverk som innehåller eller är kopplade till medicintekniska
produkter, Stockholm: SIS.
58
58
2F3
THE ROAD TO CE FOR MEDICAL DEVICES IN COOPERATION WITH INTERTEK ´S SWEDISH
MDD NOTIFIED BODY
1
1
Anneli Wiedenkeller
Intertek Certification, Regulatory Services, Torshamnsgatan 43, Box 1103, 164 22 Kista, Sweden
1. Introduction
As a manufacturer, importer or distributor of medical devices you are obliged to follow a variety of rules and regulations. In
order to sell your product(s) in Sweden and other countries within EU it is especially important to know and comply with the
applicable medical device directive (93/42/EEC “MDD” or 90/385/EEG “AIMDD” or 98/79/EG “IVDD”) and to understand
the supervising role of the Notified Body (products in higher risk classes).
2. Scope and Obligations
93/42/EEC (“MDD”) [1] is the applicable directive for many medical devices and the main scope for Intertek´s Swedish
Notified Body. The directive includes definitions, classification rules, requirements on both the manufacturer and the
product(s), different conformity roads for CE fulfillment and requirements on national authorities and notified bodies. For a
first time reader the directive might give a messy impression, but a good cooperation with your Notified Body can give you
the right understanding of the requirements and help you to be in control. To take responsibility of the safety and
effectiveness of your product(s). The requirements are extensive but can actually be summarized in a few pages stated in the
Essential Requirements (annex I).
3. The road to CE in cooperation with Intertek´s Swedish MDD Notified Body
A simplified picture of the Intertek process is:
CE: Manufacturer & Product MDD review
Step 1: Revision/audit for certification
Technical File review*
Step 2: Revision/audit for certification
EC Certificate
Repeated
2
*Answer
requested in 30
days/repeated
reports until
closure of all
NonConformities.
Optional use of Testing Services
Quality System/process review
Pre-review
•Revision/audit: MDD (+ISO13485, optional)
•Sample surveillance Technical File reviews*
www.intertek.se
References:
[1] 93/42/EEC http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=CELEX:31993L0042:en:HTML
59
THE IMPACT OF ROHS ON THE MEDICAL DEVICE INDUSTRY
1
2F4
Anna Forsgren1
Intertek Chemistry, Health and Environmental Services, Torshamnsgatan 43, Box 1103, 164 22 Kista, Sweden
1. Introduction
The European Union’s RoHS Directive 2011/65/EU, or recast RoHS, (Restriction Of Hazardous Substances in electrical and
electronic equipment (EEE)) will from 22nd of July 2014 include medical devices [1]. This abstract outlines the main
obligations under RoHS, and discusses their potential impact on the medical device industry.
2. RoHS scope and obligations
The aim of RoHS is to reduce the use, in EEE, of certain substances hazardous to the environment and human health. The
Directive restricts the use of Lead, Hexavalent Chromium, Mercury, Polybrominated Biphenyls (PBB) and Polybrominated
Diphenylethers (PBDE) to a maximum concentration of 0.1 w/w% and the use of Cadmium to 0,01 w/w% . The restrictions
apply to each homogenous material in the product. The recast RoHS Directive has a broader and clearer scope than its
predecessor, which entered into force in 2006. New categories such as medical devices and monitoring and control
instruments are now included and will be phased in over the coming years.
One important reason behind the recast of the RoHS Directive was the aim to create a simpler, more effective and more
enforceable Directive. With the recast RoHS, conformity assessment and CE marking have been introduced as the way to
show compliance. For manufacturers of medical devices with any function dependent on electricity (or electromagnetic
fields), the most important new obligations are to ensure that the substance restrictions of the Directive are met, to implement
appropriate processes for the conformity assessment and to compile the necessary RoHS documentation for the technical file.
The conformity assessment can be done through self-verification, and there is a harmonized standard available; EN
50581:2012 “Technical documentation for the assessment of electrical and electronic products with respect to restriction of
hazardous substances” available to explain and clarify this process.
3. Impact on the medical device industry
Due to the substance restrictions, it might become necessary to substitute or modify materials and components in the product.
Subsequently, these modifications may require reliability testing, validation or clinical trials and submittal of new data to
Notified Bodies for compliance with other Directives and standards. This process may take up to 2,5 years [2]. If materials
cannot be substituted, it may be necessary to apply for an application exemption. In addition, creating the infrastructure to
produce and maintain correct technical documentation on RoHS compliance has proven resource- and time-consuming and
may, in addition to substance substitution, take up to a year to complete. It is therefore important to start the compliance
work several years before the deadline.
The cost to implement RoHS largely depends on the number of suppliers, whether materials need to be substituted or new
exemptions will be required etc. For a complex and new product, the cost for RoHS compliance could be 10% of the turnover
of the product. The approximate annual compliance cost for the medical devices sector has been estimated to 400 – 1 600
million Euros [3].
Article 2(2) of the recast RoHS requires all medical devices made available on the market (i.e. any supply) to not contain any
of the six restricted substances, unless specifically excluded. Medical devices sold before 2014 and later refurbished and sold
to second users, would then be non-compliant. This will have a major negative environmental and economic impact and it
has therefore been suggested that this article of the recast Directive [4] is modified.
4. Discussion
The availability of RoHS compliant medical devices will be affected if the industry does not start the RoHS compliance work
well ahead of applicable deadlines, since ensuring that the medical devices are in compliance with RoHS might take up to
three years if validations of new materials or new exemptions are required. Also, the availability of secondary equipment will
be affected if Article 2(2) of the Directive is not changed. Manufacturers should expect that RoHS compliance will require
hard work and investments. However, these costs can be reduced with the implementation of sound processes for RoHS
compliance, using the harmonized standard and experience in the field.
References
[1] Directive 2011/65/EU of the European Parliament and of the Council of 8 June 2011 on the restriction of the use of
certain hazardous substances in electrical and electronic equipment (recast)
[2] Goodman, P., Review of Directive 2002/95/EC (RoHS) Categories 8 and 9, 5 (2006)
[3] Commission staff working paper accompanying the Proposal for a Directive of the European Parliament and of the
Council on the restriction of the use of certain hazardous substances in electrical and electronic equipment (2008)
[4] Mudgal, S. et.al., BIO Intelligence Service Measures to be implemented and additional impact assessment with regard to
scope changes, pursuant to the new RoHS Directive, Final Report prepared in collaboration with ERA Technology for the
European Commission, DG ENV, 345 – 354 (2011)
Figure 1: The RoHS Directive (2011/65/EU) will have an impact on the medical
device industry as manufacturers and other economic operators will need to comply
with this environmental legislation from the 22nd of July 2014.
60
60
Sammanfattningar
Innovation & utveckling i och med vården
Session 4F
61
61
4F1
Biomedical engineering research creates new inventions for the health care
industry
O.A. Lindahl1,2,3 , B. M. Andersson1,4, R. Lundström1,3, K. Ramser1,2
1 Centre for Biomedical Engineering and Physics, Umeå University, Umeå, Sweden
2 Department of Computer Science, Electrical and Space Engineering, Luleå University of Technology, Luleå, Sweden
3 Department of Radiation Sciences, Biomedical Engineering, Umeå University, Umeå, Sweden
4 Department of Applied Physics and Electronics, Umeå University, Umeå, Sweden
Abstract
The health care industry is dependent on new innovations for its survival and expansion. Health care innovations are also
important for improving patient care. Through activities at the centre for biomedical engineering and physics (CMTF) we
have generated growth both in academia at the universities and in the industry in northern Sweden. Fruitful cooperations
were generated between 26 research projects and about 15 established companies in the field of biomedical engineering. The
established researcher-owned company for business development of the research results from the CMTF, CMTF Business
Development Co Ltd, has so far launched three spin-off companies and has 15 new business leads to develop. The activities
have also increased the interest for commercialization and entrepreneurship. So far a total of nine spin-off companies have
resulted from the CMTF-research since the year 2000 that has improved the health care market in northern Sweden.
Keywords: Health care, Biomedical engineering, business development, innovation, science centre.
1. Introduction
CMTF (Centre for Biomedical Engineering and Physics) started 2000 at Umeå University (UmU) and since 2007 includes
Luleå University of Technology (LTU). It is an organization for triple-helix cooperation between scientific research,
biomedical industry and health care, with the aim of commercializing biomedical research in northern Sweden. CMTF has a
budget of 12 million Euro through the European Regional Structural Fund, North Sweden (2008-2014) and additional about
0,5 million Euro per year from other funds. The aim was a strong and sustainable organization for scientific research and
business development in northern Sweden. A further aim was a model for the development of new biomedical viable spin off
companies originated from the research results through the triple-helix activities of the center. .
2. Method
The CMTF was organized with a board of directors as-signed by the universities. The board is chosen to give the CMTF a
stable leadership and to reinsure a good cooperation in-between the two counties and the two universities as well as with the
health care industry in the region. The broad professional expertise of the board members guarantees high competence for
decision making on industrial as well as scientific matters. Before joining the CMTF, all original 26 research projects were
evaluated by the board concerning three criteria; scientific excellence, clinical and industrial relevance and scientific research
management. The evaluated and approved projects could make use of the CMTF logotype and refer to CMTF as their
research milieu. About 200 researchers and supporting staff were engaged within CMTF at the start of 2012.
A majority of the projects in CMTF has both scientific and industrial cooperation with international partners both outside EU,
e.g. Japan and USA, and within EU, e.g. Nor-way, Finland and Italy. An important step was the establishment of a research
company CMTF Business Development Co., Ltd. (CMTF BD), in 2007. The owners were the scientists/project managers
from CMTF as well as representatives from the regional innovation system in both Umeå and Luleå. This was in order to
form an organization that could be a part of the existing innovation system but with a special emphasis to launch the
biomedical engineering research results on the health care market. In 2011 the CMTF BD was expanded with two business
councils, one in Umeå and one in Luleå. The project leaders signed over the IPR to the CMTF BD through an agreement. For
identified research innovations, a contract was signed with the scientists about the sharing of future profit from the
innovation, a so called incentive agreement giving a stream of money to the researchers and one stream of money to the
company at success. The CMTF research and development was funded by several local and global organizations. The major
founder was the EU structural foundation, objective 2. A majority of CMTF BD was funded with support from private means
from the scientific leaders, Uminova Innovation Co Ltd, LTU Holding Co. Ltd. and the County councils in Västerbotten and
Norrbotten.
3. Results and conclusions
CMTF has built an academic and industrial network for triple-helix cooperation. Currently about 15 national and
international companies are involved in the CMTF projects. CMTF research has produced nine spin-off companies. Seven of
them were based on patented innovations and one is the CMTF BD. CMTF BD has started three new companies. More than
eleven patents have been filed within CMTF and 15 innovations are currently under business verification through CMTF BD
and the innovation systems in Umeå and Luleå. The triple-helix activities have also increased the knowledge and interest for
innovations and entrepreneurship among the scientists in the centre. The CMTF BD has also become a place for the CMTF
scientific leaders to meet and discuss business and innovation issues. Thus the company has contributed to the
encouragement of entrepreneurship. CMTF has also been successful to attract necessary funding. The CMTF research
network and CMTF BD are today an established triple-helix organization for the development of research into spin-off
companies in the area of biomedical engineering. This has resulted in an increased growth of the biomedical engineering
activities both in academia and in the industry in northern Sweden.
Acknowledgement
The study was supported by the European Regional Structural Fund, North Sweden
62
Abstract
Föreläsning om SLL Innovation
4F2
SLL Innovation är en decentraliserad organisation som arbetar med medarbetare, företag och
produktutveckling på plats i den offentligt finansierade hälso- och sjukvården. SLL
Innovation vänder sig både till sina egna medarbetare och samtidigt till den privata sektorns
företag som vill komma i kontakt med vården.
Företag behöver ofta stöd vid CE-märkning,kliniska utvärderingar och prövningar samt
riskanalyser etc. För att underlätta introduktionen
av nya innovationer i vården har SLL Innovation tillsammans med SLL Upphandling även
startat ett Innovationsupphandlingsnätverk som träffas en gång per kvartal.
SLL Innovation startade som ett projekt under 2010 med finansiering från Vinnova och
Stockholms läns landsting. Sedan starten har ett väl fungerande innovationssystem inom SLL
implementerats och idag arbetar fem innovationskoordinatorer och tre produktutvecklare
inom SLL Innovation, utplacerade på Danderyds sjukhus, Södersjukhuset, Karolinska
sjukhuset, Solna och Huddinge samt Norrtälje sjukhus.
För att samordna samtliga innovationskoordinatorer och produktutvecklare spelar det
månatliga utvecklingsrådet en
viktig roll. Där utvärderas idéer och projekt. Rådet är även ett forum för att diskutera
lösningar på organisatoriska frågor som ännu inte finns färdiga utarbetade rutiner för. Den
nära kopplingen till sjukhusens medicintekniska avdelningar ger dels tillgång till kompetens
men även viktiga kontakter med företag och sjukvårdspersonal. Detaljerade rutiner kring SLL
Innovations tjänster har upprättats och avtalsmallar har godkänts av SLL:s jurister
Resultat
Totalt har ca 450 rådgivningstillfällen, från den 1 april 2010 hållits av
innovationskoordinatorerna,
varav ca 20 idéer gått vidare för närmare utvärdering. Ett femtiotal
förfrågningar från företag/entreprenörer har mottagits, varav ett tjugotal projekt har
initierats inom riskanalys, klinisk prövning, behovsutvärdering och stöd vid CEmärkning.
Ett stort antal innovatörsavtal och fribrev har utfärdats sedan start i april 2010.
Produkten Stickstop som utvecklats inom ramen för SLL Innovation på
Södersjukhuset har sålts och kommit ut på marknaden.
SLL Innovation har initierat och leder, Kvinnors nätverk för en innovativ hälso- och
sjukvård som startades i början av 2010.
Ett permanent samarbete med Almi Stockholm/Sörmland har etablerats. SLL
Innovation har skrivit ett avtal som ger samtliga SLL Innovations
innovationskoordinatorer tillgång till Almis förstudiemedel.
Kontakter har knutits med samtliga övriga innovationsslussar som fått tilldelade
resurser från Vinnova.
Ett Innovationsupphandlingsnätverk har upprättats tillsammans med SLL
Upphandling. Syftet är att genom systematisk samverkan med upphandlingscheferna
kunna underlätta introduktionen av nya produkter i hälso- och sjukvården.
63
SLL Innovations verksamhet är förankrad i Landstingsstyrelsen och hos samtliga sjukhus- och
sjukvårdsdirektörer. Stockholms läns landsting har ca 45 000 anställda, ett
universitetssjukhus, flertalet akutsjukhus och närsjukhus, inklusive en stor primärvård.
Samtliga verksamhetschefer har informerats om SLL Innovations verksamhet genom särskild
marknadsföring via kommunikationsavdelningar inom hela SLL. Vårdpersonal informeras om
verksamheten genom nyhetsbrev, informationsträffar och flyers. SLL Innovation har även
utbildat ett 40-tal så kallade innovationsambassadörer. Ambassadörerna är medarbetare som
tidigare visat intresse för innovationer och dessa fungerar som en länk mellan avdelningarna
och SLL Innovation.
Sök på www.webbhotell.sll.se
64
4F3
OPPORTUNITIES FOR MEDICAL ENGINEERING INNOVATIONS IN HEALTCARE
TO IMPROVE LIFE FOR CHILDREN WITH CANCER
1
Dennis Sturm1,2, Karin Nilsson2, Anna Larsson2
Centre for Technology in Medicine and Health (CTMH), Stockholm, Sweden; 2KTH Royal Institute of Technology, Stockholm, Sweden
1. Introduction
Cancer is a disease with an increasing impact on society. The majority of patients treated for cancer are adults, only a small
percentage are children (i.e. persons younger than the age of 18 years). Children are often wrongly regarded as small adults.
However, their physiology, body composition and pharmacokinetics differ considerably from these of down-scaled adults.
The brain mass of an adult, for example, contributes with around 2% to a person’s body mass while this ratio may be 12% for
a small child.
Approximately 300 children are diagnosed with cancer in Sweden every year [1]. While it can be deemed positive that the
numbers for children affected by cancer are low, this small patient share may increase the challenge for businesses to develop
and produce profitable concepts for medical devices and solutions adapted to specific needs of children. Despite great
improvements in the survival rate of children with cancer to approximately 80% over the last 35 years there are still major
opportunities to improve healthcare tools and processes as well as to provide technology aids for daily life of children with
cancer and their family. There is thus a need to investigate the specific potentials for innovation in healthcare for children
with cancer. This need served as the motivation for this study.
2. Method
A solution-complication-question-answer (SCQA) structure governed the study. In order to gather
information on existing solutions as well as current difficulties a sequence of interviews was prepared.
In total 9 interviews were conducted with a group of selected individuals from healthcare personnel
(8) and parents of children with cancer (1). Interviewees were recruited with the help of a department
head and emphasis was laid on a heterogeneous distribution amongst the various functions in which
personnel served. Each interview was designed as an open interview and lasted between 20min and
80min. Consecutively, the interviews were transcribed.
The analysis of this transcribed information focussed on the identification of problems which can be
transformed into engineering questions and challenges. In this sense, specific opportunities for new
technical devices, processes and services were extracted from a wide set of data. Having sorted these
opportunities into categories, the study was finalised by listing suggestions for future work and
procedures in order to fulfil or resolve each identified need.
3. Results
Potential for new technology was observed and classified into three categories: 1) Needs for
information systems and their interfaces, 2) needs for more efficient processes, and 3) needs in
improving healthcare devices and products.
A major information system challenge is the modification of existing patient systems to facilitate the
presentation of information in an optimised way with regard to the needs of cancer healthcare. This
includes the ability to visualise a temporal presentation of events in the treatment (e.g. blood test
results, tendencies, start- and endpoint of a treatment, etc.) as well as the accumulation and
simultaneous presentation of information from different examinations for one patient.
While there are many possibilities to improve work processes, last, an example for a potential, new
healthcare product is presented. A need for circumventing the entanglement of tubes from the
multitude of infusions that a child with cancer often has to be connected to during treatment was
emphasised by both hospital personnel and a parent. As a suggestion for reducing this dilemma a
method to sort the tubes was designed, see Figure 1. The leaves of colourful and easy-to-clean flowers
on a plastic wire hold the tubes in order and allow for more free movements so that a child with
cancer is not more than absolutely necessary reduced in its desire and ability to play.
Figure 1: Prototype
to prevent entanglement of tubes.
4. Discussion
The study was designed as a Bachelor Thesis and resources were thus limited, in particular time. Nevertheless, it could be
shown that it is possible to identify opportunities for improving healthcare for children with cancer even within this limited
scope. A follow-up project to evaluate selected suggestions from this work is scheduled.
Furthermore, this project can be regarded as a pre-study to a Clinical Innovation Fellowship programme organised by CTMH
and Barncancerfonden in 2013/14. This 8-month programme will address the aforementioned problems with considerably
greater resources on time, manpower and budget.
The authors would like to express their gratitude to Barncancerfonden and to the Astrid Lindgren Children’s Hospital, a
division of the Karolinska University Hospital, for their support and cooperation.
References
[1] Barncancerfonden. http://www.barncancerfonden.se/PageFiles/11513/Engelska/faktablad%20barncancer%20engelska.pdf
Visited 2013-05-16
65
4F4
INNOVATION MOT INFEKTION, ETT INTERDISCIPLINÄRT
INNOVATIONSPROJEKT MOT VÅRDRELATERADE INFEKTIONER
1,2
1,2
2
1,2
Ylva Odelberg , Sjoerd Haasl , Malin Hollmark , Bertil Guve
Enheten för klinisk innovation, Skolan för teknik och hälsa, Kungliga Tekniska Högskolan, Stockholm, Sweden
2
Centrum för Teknik i Medicin och Hälsa (Karolinska Institutet - Kungliga Tekniska Högskolan – Stockholms Läns Landsting)
1
Vårdrelaterade infektioner (VRI) drabbar ca 9 % av de patienter som behandlas inom hälso- och sjukvården. Trots en ökad
medvetenhet om problemet har den siffran sedan 2009 legat stabil i de punktprevalensmätningar av förekomsten av VRI som
Sveriges kommuner och landsting genomför två gånger per år [1]. VRI kostar den svenska sjukvården 3.7 miljarder kronor
årligen [2,3]. Upp till 30 % av alla vårdskador utgörs av VRI enligt Socialstyrelsens vårdskademätning [2,4] även
internationellt sett är VRI den vanligaste avvikelsen inom hälso- och sjukvården. Prevalensen för VRI i Europa ligger mellan
5,7-19,1 % kostnaden för detta beräknas till ca 7 miljarder euro per år [2].
Enligt Socialstyrelsens definition av VRI [3], drabbas patienter av VRI till följd av sitt besök i vården (sjukhusvård eller
öppenvård) eller som en följd sin behandling. Det kan röra sig om pneumonier, urinvägsinfektion i samband med användning
av kvarsittande urinvägskateter eller postoperativa sårinfektioner, där operationssåret inte läker som det ska. Till VRI räknas
även då vårdpersonal drabbas av infektioner som en följd av sitt arbete. VRI leder till ökat lidande för patienter, längre
behandlingstider och högre sjukvårdskostnader: infekterade sår kan ta mycket lång tid att läka och utbrott av tarminfektioner
kan tvinga sjukhusavdelningar att stänga. Dessutom kan en VRI kräva antibiotikabehandling av en typ som ökar risken för
resistensutveckling. Ur ett globalt perspektiv har Sverige förvisso kommit jämförelsevis långt i arbetet med optimal
antibiotikaanvändning för att förhindra uppkomst av bakterieresistens, men resistenta bakterier sprids även här. Vad gäller
VRI krävs förebyggande arbete för att minska incidensen1 för att i den bästa av världar slippa behandla VRI överhuvudtaget.
Problematiken kring VRI handlar alltså både om infektioner som kan komma att kräva antibiotikabehandling och att en VRI
är en vårdskada, åsamkad patienten av vården.
Innovation mot infektion (IMI) är ett VINNOVA-finansierat multiprofessionellt projekt som tar ett helhetsgrepp om VRIproblematiken. Parterna i IMI kommer från akademi, vård och omsorg samt näringsliv och inkluderar en rad olika
professioner såsom läkare, sköterskor och annan sjukvårdspersonal, ingenjörer, designers, beteendevetare, biologer, m.fl.
Arbetsgruppen i IMI täcker på så sätt med sin samlade kompetens ett brett område, där folk med olika kompetens, ofta ovana
att samarbeta över professionsgränserna, gör gemensam sak och arbetar på ett innovativt sätt för en säkrare vård. IMIprojektet leds av SP Sveriges Tekniska Forskningsinstitut. Detta konferensbidrag fokuserar på den följeforskning som
bedrivs genom ett doktorandprojekt på Skolan för teknik och hälsa vid KTH.
Mål med projektet är att behovsägare och lösningsägare tillsammans arbetar fram innovativa lösningar som kan minska
förekomsten av VRI samt att beskriva en modell för hur parterna fortsättningsvis kan samverka effektivt. Projektet kartlägger
hanteringen av postoperativa sår, smittspridning med avseende på hygienteknik, medicintekniska device såsom urinkatetrar,
centrala venkatetrar (CVK) och endotrakealtuber och ska testa olika åtgärder såsom tekniska lösningar, processer och tjänster
som kan minska risken för VRI. Relevanta effektmått för utvärdering av dessa åtgärder ska tas fram.
I Sverige har vi en nollvision för vårdskador. Trots detta avlider varje år ca 1500 personer på grund av, eller som en följd av,
sina vårdrelaterade infektioner [2]. Det har vi all anledning att ändra på.
Referenser
[1] ”Punktprevalensmätning av vårdrelaterade infektioner v.42-43”, 2012, Sveriges kommuner och landsting
[2] ”Strategi för att minska vårdrelaterade infektioner i hälso- och sjukvården” HSN 1209-1142,
Hälso- och sjukvårdsförvaltningen 2012-09-17
[3] “Att förebygga vårdrelaterade infektioner – Ett kunskapsunderlag”, Socialstyrelsen 2006
[4] “Vårdskador inom somatisk slutenvård”, artikelnr 2008-109-16 Socialstyrelsen 2008
1 Antal patienter som insjuknar i VRI 66
4F5
KLINISKT TESTCENTRUM FÖR MEDICINTEKNIK I VÄSTMANLAND
1
1
2
Elisabet Rodby Bousquet , Maria Lindén
2
Centrum för klinisk forskning Västerås, Sweden. Mälardalens högskola, Västerås, Sweden
1. Samverkan för ökad medicinteknisk utveckling
Testcentrum är ett samverkansprojekt mellan Centrum för klinisk forskning, Mälardalens högskola, näringslivet och hälsooch sjukvården i landstinget i Västmanland i syfte att främja utveckling och införande av ny medicinteknik för att höja
effektivitet, säkerhet och kvalitet inom hälso- och sjukvården.
2. Vad är problemet?
Ett flertal forskare, innovatörer och entreprenörer inom det medicintekniska området upplever svårigheter att få testa sina
idéer och lösningar mot slutanvändaren i ett tidigt skede, och processen från idé till färdig produkt kan vara lång. Samtidigt
sker en snabb medicinsk utveckling inom hälso-och sjukvården som är beroende av tillgång till nya tekniska lösningar för
ökad kvalitet, säkerhet och effektivitet både vad gäller diagnostik, behandling och uppföljning. Möjligheten att med hjälp av
slutanvändaren identifiera vilka problem som nya produkter och tjänster verkligen behöver lösa skulle vara mycket viktig,
både för innovatören och för slutanvändaren; innovatören skulle få en bättre insikt i slutanvändarens problematik och
slutanvändaren skulle beredas möjlighet att få nya lösningar på befintliga problem
3. Hur går vi från idé till handling?
För att få till en lösning på detta initierade Centrum för klinisk forskning i samarbete med Mälardalens högskola ett forskaroch entreprenörsnätverk inom medicin och teknik i Västmanland med bl.a. gemensamma föreläsningar och diskussioner. Ett
flertal diskussionsgrupper och djupintervjuer genomfördes med nyckelpersoner inom näringslivet, akademin, hälso- och
sjukvården, medicintekniska avdelningen, upphandlingsenheten mm för att identifiera svårigheter att komma från idé till
färdig lösning och möjligheterna att öka samverkan mellan forskare och entreprenörer inom medicinteknik och hälso- och
sjukvården för att snabbare få tillgång till nya tekniska lösningar.
4. Initiala resultat
Denna utökade samverkan mellan medicin och teknik bidrog till uppstart av ett flertal nya utvecklingsprojekt bl.a. med
innovation, utveckling och utvärdering av nya tekniska lösningar för förbättrad diagnostik inom barn och ungdomspsykiatrin.
Ett kliniskt testcentrum byggs nu upp på sjukhuset med sjukhusmiljö, boendemiljö och virtuell miljö för att underlätta klinisk
testning av olika medicintekniska lösningar i form av produkter, processer och metoder. Testcentrum drivs via Centrum för
klinisk forskning i landstinget Västmanland i ett nära samarbete med Medicintekniska avdelningen, Mälardalens Högskola,
NovaMedTech, ALMI, Västerås Science Park, Länsstyrelsen m fl. Testcentrum erbjuder en möjlighet att testa idéer och
lösningar i ett tidigt skede men även test och klinisk utvärdering under senare utvecklingsfaser. Det erbjuder en testmiljö
riktad mot hälso- och sjukvården med medicinsk specialistkompetens inom ett flertal områden som bl a. psykiatri och
onkologisk kirurgi. Testcentrum förbereder även testmiljö för innovationer och produkter riktade mot barn, vuxna och äldre
med flerfunktionshinder.
67
4F6
METIS – EN MODELL FÖR REPETERBAR LÅNGSIKTIG INNOVATION OCH UTVECKLING AV
EHÄLSA INOM PREHOSPITAL AKUTSJUKVÅRD
1
Bengt Arne Sjöqvist1, Robert Sinclair2, Bo Norrhem3, Marika Hellqvist-Greberg4
Signaler och System, Chalmers, Göteborg 2 Hälso- och sjukvårdsavdelningen, Västra Götalandsregionen, Göteborg
3
Lindholmen Science Park, Göteborg 4 Regionutvecklingssekretariatet, Västra Götalandsregionen, Göteborg
Introduktion
Den prehospitala akutsjukvården står inför stora utmaningar. Nya vårdprocesser och metoder, samt ökande krav på
behandlingsresultat, säkerhet, kvalitet, uppföljning och effektivitet kräver samverkan och informationsutbyte mellan många
olika aktörer och system, såväl som stödjande IKT/eHälsa. Denna situation skapar därför stora möjligheter för utveckling och
innovation av eHälsa inom området. För att täcka hela kedjan från händelse till vård på rätt plats, i rätt tid och på rätt nivå,
krävs ett flertal samverkande komponenter från olika leverantörer. Krav på standardisering, helhetstänkande, vårdkunskap,
utvärdering och tester i autentiska miljöer, samt öppenhet mellan alla inblandade aktörer är därför nödvändigt för att nå
långsiktig framgång. Dessutom måste även komplexiteten när det gäller teknik, samverkande aktörer, juridiska frågor etc.
beaktas i innovations- och utvecklingssammanhang.
Projektbeskrivning
Projektet Metis drar fördel av en unik regional situation när det gäller tillgång till aktörer och kunskapsdomäner för att skapa
en modell för innovation och utveckling av processtödjande eHälsa inom prehospital akutsjukvård. Modellen skall
möjliggöra repeterbar långsiktigt hållbar utveckling, innovation, tillväxt och omsorg, men också stärka Sveriges ”frontline”
position som leverantör av testade och validerade lösningar, vårdmodeller och produkter riktade mot hela
tillämpningsområdet.
Grundläggande i Metis är en "Öppen Innovation/Open Innovation" influerad aktiv samverkan mellan näringsliv, vårdgivare
och akademi, och ett signifikant antal aktörer från dessa parter är också representerade i projektet. I modellen ingår bl.a. en
samverkansarena benämnd Metis Forum, inkl. websida www.metis.nu, samt en handbok/handledning, Metis Handbok. Den
senare är ett ”levande” dokument som innehåller råd, rekommendationer och information att beakta och ta ställning till då
man t.ex. önskar utnyttja någon av de testbäddar Metis har tillgång till. Exempel på innehåll är juridik/legala frågor, IT-miljö
och krav, tekniska förutsättningar, sjukvårdsorganisation och prövningsmetoder. Metis tar inledningsvis sin utgångspunkt
regionalt, men ambitionen är nationell och på sikt internationell.
Resultat
Metis har nu slutfört sin första projektfas. I denna har Metis Forum etablerats, dess tänkta samarbetsformer och
”programförklaring” fastställts och dokumenterats, samt en första version av Metis Handbok producerats. I presentationen
kommer projektet Metis, aktuellt läge, erfarenheter och resultat, samt planer för framtiden att redovisas.
68
Sammanfattningar
Modellering
Session 2G
69
69
2G1
THE HEART AS A DISPLACEMENT PUMP: A NOVEL CARDIAC MODEL
Elira Maksuti1, Jonas Johnson1, Anna Bjällmark1,2, Michael Broomé1,3
Department of Medical Engineering, School of Technology and Health, Royal Institute of Technology, Stockholm, Sweden
2
Department of Molecular Medicine and Surgery, Karolinska Institute, Stockholm, Sweden
3
ECMO Department, Karolinska University Hospital, Stockholm, Sweden
1
1. Introduction
A common approach to cardiac mechanics is to consider the heart as a squeezing pump emptying its content with a
considerable change in outer volume. In more recent studies [1], it was suggested that the heart can be described as a
displacement pump with the atrioventricular (AV)–plane acting like a piston unit. This theory was supported by cardiac
imaging and provides a better explanation of ventricular pumping action in healthy individuals [2]. Simulation models are
useful tools for understanding complex systems such as the heart. The widely used time-varying elastance function in cardiac
simulation models is based on a reverse engineering approach, where experimental observations have been used to create
clinical relevant pressure and volume changes in the cardiac chambers. These models are mainly descriptive and have a
limited connection to physical reality. We therefore propose a novel model of the left heart based on physical modelling of
the AV-plane displacement in a fixed outer volume providing a better understanding of cardiac mechanics.
2. Methods
The left heart model (Figure 1a) is composed of an upper chamber (the atrium) and a lower chamber (the ventricle). One-way
valves are located between the two chambers (mitral valve) and between the ventricle and the artery model (aortic valve).
The piston has different areas in the upper and lower crown and it is pushed downwards by an external force during the
contraction phase (ventricular systole). This causes the opening of the outlet valve, while the inlet valve is closed. During the
relaxation phase (ventricular diastole) the external force ceases, the outlet valve closes, the inlet valve opens and the piston
goes back to its initial position by an hydraulic return due to the differential area between the two crowns of the piston. This
pump model is then connected in a closed loop to a vascular model mimicking resistive and elastic properties of the vascular
tree. The only input to the model is a trapezoidal function force during the contraction phase and this force is set to zero
during the relaxation phase. Parameter selection is done using values from literature or by calculating the parameters through
physical laws. The domain-independent bond graph formalism (Figure 1b) is chosen in this work and the model was
implemented in the software platform Dymola (Dassault Systèmes, France) based on the object-oriented programming
language Modelica.
3. Results
The results of the simulations show a realistic dynamic behaviour of the model in relation both to ventricular filling and
contraction. Pressure and flow profiles matches the ones shown in standard physiology textbooks and the piston velocity
curve follows a Tissue Doppler Imaging profile measured in proximity to the AV-plane (Figure 1c).
4. Discussion and Conclusion
Model output is realistic despite the use of a simulation method not previously published. Future development of the model
includes the consideration of the atrial contraction and the non-linear valve resistance, and also to test how the model adapts
to changes in preload (filling) and afterload (vascular impedance) in clinical scenarios. Moreover, a sensitivity analysis
could reveal which parameters in the model play crucial roles. To summarize, the suggested model shows physiological
dynamics, which could be interpreted as a further proof of the concept that the heart behaves as a displacement pump.
References
[1] S. Lundbäck, “Cardiac Pumping and Function of the ventricular Septum”, Acta Physiologica Scandinavica Supplementum, vol. 550, pp.
69-73 (1986).
[2] Carlsson M., Cain P., Holmqvist C., Stahlberg F., Lundbäck S. and Arheden H. (2004) Total heart volume variation throughout the
cardiac cycle in humans. American Journal of Physiology Heart and Circulatory Physiology 287, H243-H250.
(a)
(c)
(b)
Figure 1: (a) Physical modelling of the heart; (b) equivalent bond graphs model; (c) simulation results.
70
2G2
Dielectric characterization of osteosarcoma cells in the 2-50 GHz range for microwave hyperthermia
1
Robin Augustine1*, Dragos Dancila1, Marjam Ott2 and Anders Rydberg1
Microwave Group, Division of Solid State Electronics, Department of Engineering Sciences,
Uppsala University,Sweden
2
Division of Applied Materials Science, Department of Engineering Sciences,
Uppsala University, Sweden
1. Introduction
This work aims at characterization osteosarcoma cells for finding out frequencies which could be used for treatment
of bone cancer. The power dissipated in a dielectric medium in a (time-varying) electromagnetic field is dependent
on the dielectric permittivity of the medium. Therefore, when examining the potential effects of microwave
radiation on cells, it can be useful to know the permittivity of the cells. In this experiment, the dielectric permittivity
of various cell types was measured using a coaxial probe, connected to a vector network analyzer. The Agilent
coaxial probe measures the reflection coefficient of guided electromagnetic (EM) waves at its tip and the associated
85070E software then calculates the dielectric permittivity of the medium.
2. Materials and Method
The cells are modeled as small spheres and the culture medium is homogeneous, the dielectric permittivity of the
cells can be calculated from measurements of pure culture medium and cell suspension permittivities using
Maxwell’s mixture equation [1].The permittivity measurements were performed using a 200 mm coaxial probe
(Agilent 85070E Dielectric Probe Kit) connected to a vector network analyzer (Agilent E8364B PNA series) via a
semi-rigid coaxial cable (Wiltron V120-12). The material under test (MUT) was raised up to the probe so that the
tip was immersed (at least 5 mm) into the suspension. The coaxial probe can only be used for liquid samples or soft
semi-solids, since the tip has to be inserted into the sample. Therefore, measurements were performed on
suspensions of cells in culture medium [2]. The permittivity of the cells was calculated from the difference in
permittivity between culture medium and cell suspension using Maxwell's mixture equation. A concentration of
2700000/ml Osteosarcoma (Soas-2) cell line was used to make the cell suspension. The experiments were carried
out at room temperature, 22°C.
3. Results and Discussion
Figures 1(a) and 1(b) show the arithmetic means of the measurements (solid curves) and 95% confidence interval
(dashed curves) of Osteosarcoma cells and pure culture medium respectively. Figure 1(c) shows the arithmetic mean
of the differences in measured permittivity between cell suspension and culture medium, and the associated 95%
confidence intervals. For frequency samples where the value 0 is located inside the confidence interval, there is no
statistically significant difference. For cancerous bone cells with a concentration of 2700000/ml, only the imaginary
part showed significance, and only for frequencies below 15 GHz. All measurements show an increase in the
arithmetic mean of the permittivity difference at low frequencies. As a result, it could be inferred that any difference
in permittivity between cells and culture medium should primarily be sought at the low end of the spectrum.
4. Conclusion
We measured the dielectric properties of osteosarcoma cell lines in the range of 2-50 GHz. The results show
significant difference in imaginary part of complex permittivity with respect to culture medium. The obtained
results could be crucial for our future development of microwave based treatment of bone cancer. SciLife platform
is acknowledged for providing us with cell lines.
References
[1] S. Takashima, Electrical Properties of Biopolymers and Membranes. Adam Hilger, Bristol and Philadelphia
1989.
[2] Zhadobov et al., Complex Permittivity of Representative Biological Solutions in the 2-67 GHz
range.Bioelectromagnetics 33(4):346-355, 2012.
(a)
(b)
(c)
Figure 1. Arithmetic means of the measurements (solid curves) and 95% confidence interval (dashed curves).
(a) Soas-2 cell line, (b) Culture medium and (c) difference.
71
71
2G3
VARIATION IN HIP CONTACT FORCE DURING GAIT DUE TO NECK SHAFT ANGLE AND
FEMORAL ANTEVERSION
Priti Yadav1, M.Tech. , Eva Pontén2, MD, PhD, and Elena M Gutierrez-Farewik 1, 2, PhD
1
Department of Mechanics, Royal Institute of Technology, Stockholm, Sweden.
2
Department of Women’s and Children’s Health, Karolinska Institutet, Stockholm, Sweden
1. Introduction
Children with CP often have normal skeletons at birth [1] but lower limb skeletal deformities often develop thereafter. Coxa
valga (increased femoral neck shaft angle) and torsional deformities (femoral anteversion) are frequently observed in children
with CP and can lead to hip dislocation [2]. The femoral neck shaft angle (NSA) and femoral anteversion (FA) angles change
during development in typically-developing (TD) children, and are commonly 20˚ to 50˚ greater in children with CP [3]. The
hip contact force and muscle forces play a crucial role in the development of these deformities during skeletal growth. Our
hypothesis is that the forces on the femur during walking can influence growth and deformity development. The aim of this
study is to evaluate how varying neck shaft angle and femoral anteversion affect hip contact forces during gait in TD
children.
2. Method
The subjects considered in this study were 10 TD children between 5 and 17 years of age. For this abstract, results from only
one 10-year old girl are illustrated and discussed. Gait analysis was performed using an 8-camera motion analysis system
(Vicon MX40) with 2 force platforms (Kistler). From the experimental data, a generic musculoskeletal model (SIMM,
Musculographics Inc.) was scaled to each subject. The hip joint was defined as a ball and socket joint. A deform tool was
used at the proximal femur to allow variation of NSA and FA. The ranges considered in the analysis for NSA and FA are
125°-150° and 15°-60° respectively. The expected muscle activation patterns for normal walking were determined by
performing inverse dynamic analysis and static optimization in SIMM. The computed muscle activations together with
external forces were used as input for a second inverse dynamic analysis to compute the hip contact force. The peak hip
contact force as well as computed muscle forces at this instance were analysed.
3. Results
The peak hip contact force on the femur and its variation with NSA and FA are shown in Figure 1. The peak hip contact force
was observed at contralateral toe-off position, which is approximately 20% of the gait cycle. The inferior and posterior
components of peak hip contact force increase with increasing NSA and FA, while the medial-lateral component remains
almost unchanged with increase in NSA and FA. Results also show that peak hip contact force acts posteriorly and laterally
for the considered range of NSA and FA.
4. Discussion and Conclusion
Muscles lines and points of action change with varying NSA and FA, thereby changing muscle forces. These changes in
muscle forces cause the computed increase in peak hip contact force with increasing NSA and FA. Future studies can be
performed to investigate whether this increase in peak hip contact force may inhibit the endochondral growth by reducing the
effect of tensile stress on the femoral neck in a growing child
References
[1]Lundy et al, Journal of Pediatric Orthopedics. 18: 528–34, 1998.
[2]Gage, Schwartz, Koop, Novacheck, The Identification and Treatment of Gait Problems in Cerebral Palsy, MacKeith
Press 2009.
[3]Davids et al, The Journal of Bone and Joint Surgery Am, 85: 481-488, 2003.
Figure 1: Peak hip contact force on the femur (at contralateral toe-off) in all directions as a function of neck shaft angle and
femoral anteversion.
72
2G4
The information contained in a mechanistic model yields improved biomarkers compared
to existing methods when diagnosing diffuse liver disease
Markus Karlsson1, Mikael Forsgren1,3,4,5, Olof Dahlqvist Leinhard3,4, Örjan Smedby3,4, Peter Lundberg3,4, Gunnar Cedersund1,2
1
Dpt of Biomedical Engineering, Linköping university, Linköping, Sweden. 2 Dpt of Clinical and Experimental Medicine, Linköping
University, Linköping, Sweden,3Dpt of Medicine and Health, Linköping University, Linköping, Sweden,4 Center for Medical Image Science
and Visualization, Linköping University, Sweden,5Wolfram MathCore AB, Linköping, Sweden
1. Background
Liver diseases are a growing problem in the westernized world, and it is typically hard to evaluate the pathology in the early
stages. The current gold standard is a liver biopsy, but this method has many problems, such as risks, and its regional
assessment. A promising alternative and complement is Dynamic Contrast Enhanced Magnetic Resonance Imaging (DCEMRI), which provides 3D time-series of the contrast agent (CA) uptake. However, current methods only analyze this
information from a purely data-driven point of view. Such an analysis thus disregards the fact that uptake processes are
possible to model mathematically, and that the addition of such knowledge may improve the diagnosis. We here show that
such an improvement is indeed possible.
2. Method and Results
Using data from healthy human subjects [1] and a standard clinical MRI protocol, we developed an identifiable mechanistic
model, based on a few compartments described by ordinary differential equations and standard kinetic expressions [2]. The
model was validated on independent validation data, using several-fold higher CA concentrations measured in blood samples
[2], see Figure 1. We then showed that the model can describe also diseased patients, and that the estimations are
significantly and crucially improved by the use of nonlinear mixed-effect modelling [3]. We then finally showed that the
estimated parameters allows for a more clearcut separation between different patient groups compared to what other
previously developed methods [4] could obtain. This was demonstrated using various statistical measures, which all pointed
to the same conclusion [3], see Table 1.
3. Summary and significance
In summary, we have showed that the information contained in our mechanistic model does improve the patient-specific
diagnosis that can be done based on MRI data, compared to methods that does not use such information. This mechanistic
model therefore opens the door to the development of a link between the multi-level models developed for instance in the
virtual liver network and even more refined clinical end-usage, such as spatially resolved models to be used in surgical
planning for cancer patients.
References
[1] O Dahlqvist-Leinhard et al, Eur. Radiol. 2012:22(3);642-53 [2] M Forsgren et al, submitted [3] M Karlsson et al,
submitted [4] Norén et al, Eur Radiol. 2013;23(1):174-81
Table 1: Examples of tests showing that the new model
parameters (kph and khp) serve as superior diagnostic
biomarkers (in bold) compared to existing biomarkers
(khep, LSC_N10 and LSC_N20). In particular, our twodimensional approach, combining the two model
parameters are the most superior, also compared to
combinations of existing biomarkers. More tests than
these have been applied, including ROC-curve analysis.
Figure 1: Agreement with independent validatation data (red) and
the model (green). In this case, the model has not been fitted to this
data, and the measurements have been done in an new way.
73
73
2G5
FLOW CHARACTERISTICS IN THE AORTIC ARCH
1
1
1
2
3
3
L. Prahl Wittberg , S. Van Wyk , L. Fuchs , E. Gutmark , I. Gutmark-Little , P. Backeljauw
1
2
3
KTH Mechanics, Stockholm, Sweden. University of Cincinnati, Ohio, USA, Cincinnati Children’s Hospital, Ohio, USA
1. Introduction
The blood flow in the human aortic arch and how it is affected by geometrical anomalies is the focus of this study. The
underlying reason for this is that hemodynamics is believed to play an important role in localizing vascular diseases.
Anatomic cardiovascular defects can be characterized by changes in the shape of the arch geometry, including widening or
narrowing of the aortic diameter, as well as lengthening of parts of the arch. Malformations as mentioned above may lead to
undesired changes in blood pattern directly affecting the fluid mechanical forces acting on the vessel wall. Moreover, the
transport of Red Blood Cells (RBC) may be altered as it depends on the flow itself, also influencing the wall shear stresses.
Since cardiovascular anomalies are often found in patients having the genetic disorder Turners Syndrome (TS), the flow in
the aortic arch in this patient population will be investigated. The main objective is to assess the differences in flow
phenomena occurring in the different geometries studied and how these changes affect the local blood distribution as well as
wall shear stresses.
2. Method
Data from Cardiac Magnetc Resonance Imaging (CMR) have been used in order to reconstruct the geometries of the aortic
arch from four patients having TS. The four geometries studied are one normal aortic arch (TS normal), an arch having a
dilated ascending aorta (TS dilated), an arch characterized by a constriction found in the descending aorta (TS constriction)
and an aortic arch with an elongated transverse aorta (TS ETA).
To fully resolve the flow field in time and space, the Navier-Stokes equations of an incompressible fluid, where the fluid in
this case is represented by a mixture of RBC and blood plasma, are solved using OpenFOAM-1.6. The mixture density is
considered as a function of the RBC and plasma densities. To model the evolution of the RBC mixture, a mass transport
equation is solved, where the RBC are acting as an active scalar that is coupled to the blood viscosity, modeled by the
Quemada rheological model [1]. The inflow into the ascending aorta is pulsatile, representing a heart pulsation cycle
representing a volume flow of 5 L/min at 60 BPM (Beats Per Minute). At the outlets, i.e. the brachiocephalic branch, the left
common carotide, the left subclavian branch and the descending aorta, a pressure condition is set that allows for a temporal
evolution of the pressure. The walls of the aortic arch are assume to be rigid, and the distribution of RBCs at the inlet are
corresponding to what has been observed in experimental studies of large arterial scaled tubes [2], where the bulk RBC
volume fraction is set to 45%.
3. Result & Discussion
The results show a clear geometry effect, depict for TS dilated
and TS constricted in Fig. 1 displaying the normal velocity,
and the in-plane velocity components. Common for all aortas
is that recirculation zones are formed at approximately the
same time in the cardiac cycle. However, the occurrence of
recirculation zones is increased in TS constricted and TS
ETA, in which three recirculation zones are formed (marked
by the red rings in Fig. 1). The recirculation zones are found
to coincide with areas displaying low time averaged wall
shear stress and highly fluctuating behavior of the wall shear
stress. The interest in understanding the locations of
recirculation zones combined with the wall shear stress
behavior is for example connected to identifying sites prone
to develop atherosclerosis.
As indicated above, the presentation of this work regarding
the flow and corresponding forces occurring in different aortic
archs will reveal a clear geometry effect. Also, the
distribution of the RBCs along with the feature that the blood
is found to leave though the branches on the arch to a greater
extent for TS constricted and TS ETA as compared to TS
normal and TS dilated are other topics that will be discussed
within the scope of this work.
References
[1] D. Quemada, Rheologica Acta, 17(6), 632-642 (1978).
[2] R. M. Tiggelaar, T. T. Veenstra, R. G. P. Sanders, J. G. E.
Gardeniers, M. C. Elwenspoek, and A. van den Berg,
Talanta, 56, 331-339 (2002).
74
Figure 1: Snapshots of the normal velocity component
taken at a point in time of the cardiac cycle
corresponding to t/T=0.254 for TS dilated (top) and TS
constriction (bottom). For two additional cross
sections, represented by E and H in the figure, the
normal and the in-plane velocity components are
displayed.
Sammanfattningar
Medicinsk bild- och signalbehandling
Session 3G
75
75
3G1
ADVANCED PROSTHETIC CONTROL THROUGH
AN OSSEOINTEGRATED BIDIRECTIONAL INTERFACE
1,2
1
1
2
Max Ortiz-Catalan , Bo Håkansson , and Rickard Brånemark
2
Chalmers University of Technology, Gothenburg, Sweden, Sahlgrenska University Hospital, Gothenburg, Sweden.
1. Introduction
Although myoelectric prostheses have been clinically implemented since the 1960’s, they are still far from the functionality
of their biological counterpart. It is a widely known fact that the lack and instability of physiologically appropriate control
signals are the bottleneck of the field. Implantable neuromuscular interfaces could provide enough and long-term stable
signals [1], however, the permanent communication with implanted devices is a major constraint that has hindered this
solution for decades. In order to overcome this problem, we have developed a permanent bidirectional interface into the
human body, the Osseointegrated Human-Machine Gateway (OHMG).
2. Method
The OHMG is an enhancement of the OPRA Implant System [2], which has been used to treat over 200 patients worldwide
(Figure 1). The OHMG’s modular design allows customization of the neuromuscular interfaces according to the patient’s
anatomy and prosthetic needs. It initially comprises epimysial and cuff electrodes combinations which account for up to 12
contacts. The recording features of the cuff electrodes have been optimized in a frog sciatic nerve model [3]. Furthermore,
analog electronics and an advanced control system based in pattern recognition have been developed (BioPatRec) [4].
Figure 1: The Osseointegrated Human-Machine Gateway (OHMG), an enhancement of the OPRA Implant system [2]. Animation to
illustrate the concept at: http://youtu.be/w8hlziytLkM
3. Results
20 non-amputees and 5 amputees, with and without OPRA, have shown successful real-time control of multifunctional
prostheses using BioPatRec [4]. Furthermore, simultaneous control has also been achieved with superior real-time
performance over individual control [5]. A new semi-discrete tripolar configuration was found to increase the signal to noise
ratio in neural recordings, but more importantly, it provides additional channels for neural information [3]. Finally, The
OHMG has been successfully implanted in the first patient and preliminary tests are currently ongoing. This is the first time
that neuromuscular electrodes have been permanently implanted in amputee patient in order to interface limb prostheses.
4. Discussion
Preliminary clinical results show that the OHMG has the potential to allow permanent access to implanted electrodes, and
once validated, it will open new possibilities for more advanced and natural prosthetic control. Long-term clinical studies are
required to prove the benefits of implantable interfaces in prosthetic control. The early clinical results from the OHMG study
will be reported.
References
[1]
M. Ortiz-Catalan, R. Brånemark, B. Håkansson, and J. Delbeke, “On the viability of implantable electrodes for the
natural control of artificial limbs: Review and discussion.,” Biomed Eng Online, vol. 11, p. 33, Jun. 2012.
[2]
K. Hagberg and R. Brånemark, “One hundred patients treated with osseointegrated transfemoral amputation
prostheses—rehabilitation perspective,” J Rehabil Res Dev, vol. 46, no. 3, pp. 331–344, 2009.
[3]
M. Ortiz-Catalan, J. Marin-Millan, J. Delbeke, B. Håkansson, and R. Brånemark, “Effect on signal-to-noise ratio of
splitting the continuous contacts of cuff electrodes into smaller recording areas,” J Neuroengineering Rehabil, vol.
10, no. 22, 2013.
[4]
M. Ortiz-Catalan, R. Brånemark, and B. Håkansson, “BioPatRec: A modular research platform for the control of
artificial limbs based on pattern recognition algorithms,” Source Code Biol Med, vol. 8, p. 11, 2013.
[5]
M. Ortiz-Catalan, B. Håkansson, and R. Brånemark, “Real-time classification of simultaneous hand and wrist
motions using Artificial Neural Networks with variable threshold outputs,” in Proceedings of the XXXIV
International Conference on Artificial Neural Networks (ICANN), Amsterdam, May 15-16, 2013.
76
3G2
QT INTERVALS AND HEART RATE VARIABILITY FROM HOLTER-ECG:S
IN CHILDREN WITH LONG QT SYNDROME
1
1
1
2
1
Anna Lundström , Marcus Karlsson , Gabriel Granåsen , Håkan Eliasson , Annika Rydberg , Urban Wiklund
1
2
Norrlands universitetssjukhus, Umeå, Sweden, Astrid Lindgrens barnsjukhus, Stockholm, Sweden
1
1. Introduction
Congenital long QT syndrome (LQTS) is an inherited autosomal dominant disease that affects the cardiac ion channels,
leading to a prolonged ventricular repolarisation with risk for torsade de pointes and sudden cardiac death. The characteristic
findings on the electrocardiogram (ECG) are a prolonged corrected QT interval (QTc) and T wave abnormalities. The
purpose of this study was to longitudinally evaluate QTc, heart rate variability (HRV) and the influence of prophylactic
medication, in two-channel Holter-ECG recordings from children/adolescents with LQTS.
2. Methods
Included in this retrospective study were genetically verified LQT1, LQT2 or LQT3 patients that during the age of 0-18 years
underwent at least one 24-hour ECG (Holter) recording. In total, we analysed 364 Holter recordings from of 79 patients (42
female, 53%). The patients were followed longitudinally for a median of 3 years (0-10) and the average amount of Holter
recordings per patient were 4,5 (1-17). A control group consisting of 39 healthy children and youths, with a median age of
10.6 (1-18) years underwent echocardiography and presented Holter-ECG:s with normal findings. The LQTS patients were
all managed at the Department of Pediatric Cardiology at Norrland´s University Hospital or Astrid Lindgren Children´s
Hospital, Karolinska – Solna. Since a large part of the Holter recordings had been performed with a system that did not
include any QT-analysis, we have developed software for automatic beat-to-beat analysis of QT and RR intervals. All QT
values were filtered using an algorithm that eliminated inaccurate measured values. The validity of the software has
previously been proven through comparison against >14000 manually on-screen measurements of heartbeats from 10
children with LQTS and 10 healthy children. In this study, all analyses were based on 24-hour averages of QTc and indices
from power spectrum analysis of HRV. Non-parametric statistical methods were used for all comparisons.
3. Results
The LQTS patients were, as expected, found to have a significantly longer mean QTc interval and a longer RR interval
during the 24-hour recording when compared to the control group. When the QTc values were plotted out in relation to age, a
majority of the patients (n=53, 68%) had a QTc over 460 ms, 20 patients had a borderline value between 440-460 ms and
four had a QTc under 440. The LQTS patients showed a decrease in low-frequency (LF) variability when compared to the
control group. Fifteen LQTS patients had undergone a Holter recording before the start of medication and later underwent a
recording while on Beta-blocker therapy. When comparing the QTc and HRV parameters for these 15 patients before
medication and on medication, a significantly longer RR interval and lower PLF/PHF ratio were found.
4. Discussion
To our knowledge, there are few (if any) previous studies that have analysed QT intervals and HRV from Holter-ECG
recordings in children with LQTS. However, our results regarding QTc and mean RR interval are in agreement with previous
studies based on short ECG recordings. The reduced PLF/PHF after betablockade could be an indicator of reduced
sympathetic activity, acting as a protection against arrhythmias. Our on-going research is based on this database of nearly
400 recordings, and our current analyses aims to determine whether HRV can be used for risk assessment in LQTS.
77
77
3G3
Multivariate Classification of Cardiac Autonomic Function and Echocardiographic Abnormalities
1
1
Gabriel Granåsen , Ole B Suhr , Urban Wiklund
1
Umeå University Hospital, Umeå, Sweden.
1
1. Aims:
Abnormalities in the function, physiology and the regulation of the heart can be diagnosed using echocardiography (ECHO)
and analysis of heart rate variability (HRV). Patients with transthyretin amyloidosis often present cardiac hypertrophy and/or
autonomic dysfunction. We used a novel approach to analyse the relationship between these findings, using a combination of
dimension reduction techniques and model based clustering. The aim of this work was to develop a model for future
predictions of the current state of the disease in context of HRV and ECHO abnormalities
2. Methods
Data were obtained from 39 adult patients and 62 healthy controls. HRV indices were calculated as 24-hour averages: the
mean RR interval; the power of the very low-frequency, low-frequency and high-frequency components. From ECHO we
used: posterior wall thickness, septal thickness, left ventricular end diastolic dimension, isovolumetric relaxation time and
deceleration time. Principal component analysis was performed to model the within modality variability of each group of
variables. The hierarchical Gaussian mixture modelling method, Mclust[1], was used to find clusters of subjects in the
resulting component scores. Models were validated using bootstrap resampling techniques.
3. Results
For each modality, subjects were classified into three groups. The cluster that mainly consisted of controls was denoted as
Normal. The most diverging cluster was denoted Abnormal. The middle cluster was denoted Borderline. All controls were
classified as normal in ECHO, and as normal (young and middle-aged subjects) or borderline (middle-aged and old) in HRV,
reflecting the well-known successive decrease in HRV with age in healthy subjects. For patients, the classification was
related to the progress of disease: 36% had normal or borderline HRV and normal ECHO; 18% had abnormal HRV and
normal ECHO; while 46% were classified as borderline or abnormal in both examinations.
4. Conclustions
The analysis successfully separated between patients with regulatory involvement but only minor structural abnormalities,
and those with both structural abnormalities and severe autonomic dysfunction. Clinically, the model can be used to predict
how subgroups of ATTR patients are classified with respect to the training material, for example for examining abnormality
patterns for patients with arrhythmia, or for quantification of progression of cardiac and autonomic complications after liver
transplantation. The presented method can also be extended to model patterns in other diseases with cardiac and autonomic
involvement.
HRV
0
PC2
1
2
3
Control HN
Control HB
Patient HN
Patient HB
Patient HA
-4
-2
0
2
PC1
4
6
-3
-3
-2
Control EN
Control EB
Patient EN
Patient EB
Patient EA
-2
-1
0
-1
PC2
1
2
3
ECHO
-4
-2
0
2
4
6
PC1
Figure 1: Results after dimensional reduction and mixed gaussian clustering. For each modality two significant principal
componetns were found with three clusters each. The clusters were named after progress of disease and relation to controls as
Normal, Borderline and Abnormal. 95% confidence ellipses for controls are marked with dashed lines and cluster centroids
with solid lines.
References
[1]
C. Fraley and A. E. Raftery, “MCLUST version 3 for R: Normal mixture modeling and model-based clustering,”
2006.
78
3G4
ECHOCARDIOVARIABILITY – LOW AND HIGH FREQUENCY
BEAT-TO-BEAT VARIABILITY IN ECHOCARDIOGRAPHIC SIGNALS
Amanda Albano1, Sandra Gustavsson2, Per Lindqvist2, Michael Henein2, Urban Wiklund1, Christer Grönlund1
1
Medicinsk teknik – FoU, Strålningsvetenskaper, Umeå universitet, Umeå, Sverige.
2
Hjärtcentrum, Folkhälsa och klinisk medicin, Umeå Universitet, Umeå, Sverige
1. Introduction
The cardiovascular system comprises several oscillating components, e.g. respiration (~0.3Hz, HF), Meyer waves (~0.1Hz,
LF). Since echocardiographic variables are known to be load and respiration dependent, the guidelines say that images should
be taken at end-expiration. However, this does not account for low frequency variations. This work aims at assessing this low
and high frequency beat-beat variability in healthy and diseased subjects.
2. Methods
Five young and two older healthy subjects (20-35y and 50-60y), and two patients with amyloid cardiac disease (50-70y),
participated in this pilot study. A two-minute B/CDI-mode echocardiographic exam was performed with acquisition of ECG,
respiration and blood pressure (BP) signals. Simultaneous blood flow velocity and myocardial motion echo-variables, and
systolic BP were extracted per heart-beat off-line. Variability of the unfiltered, LF (bandpassed BP), and the HF signals was
calculated using the coefficient of variation (CV). Coupling strength to Meyer waves and respiration signals was quantified
by the coherence power index (CPI). Analysed signals included: early and late peak diastolic flow velocity (E, A), peak
myocardial velocity (E’), E/E’, and E/A.
3. Results
Figure 1 illustrates the variability in the E/E’ index over a 90 second period for one healhy young and one older subject, and
one patient. In general, the echovariables had wider band spectra than BP, respiration and RR signals. Variability of
unfiltered signals was 10-30% and was lower in patients and old compared to healthy subjects. The variability in the LF and
HF bands were similar (~10%) except for the A and E/A (higher in HF band). The coupling strength (CPI) between echovariables and respiration was overall stronger (20-80%) than coupling to Meyer waves 10-50%, and was lower in patients
than in healthy subjects.
E/E’
4. Discussion
This work introduces and illustrates the concept echocardio-variability (ECV). The magnitude of the high and low-frequency
variations was similar and may influence clinical assessment. This approach seems promising for the development of novel
diagnostic indices.
Figure 1: 90 seconds E/E’ variations for a young and old healthy subject, and a patient with amyloid cardiac disease (FAP).
End-inspiration and expiration is indicated by dots and asterix.
79
79
3G5
A COMPARISON OF SHEAR WAVE ELASTOGRAPHY PUSHING SEQUENCES
1
Tim Nordenfur1, Elira Maksuti1, Erik Widman1, Anna Bjällmark1,2, Matilda Larsson1,2
Department of Medical Engineering, School of Technology and Health, Royal Institute of Technology, Stockholm, Sweden
2
Department of Molecular Medicine and Surgery, Karolinska Institute, Stockholm, Sweden
1. Introduction
Changes in stiffness of soft tissue are a sign of abnormalities. Therefore, techniques capable of estimating elasticity of tissue
can contribute in the assessment of various diseases. Shear wave elastography (SWE) is an ultrasound-based technique where
a pushing beam induces shear waves (SW) characterized by lower wave speed than longitudinal waves and that travel
orthogonally to the pushing beam direction. Tissue elasticity can then be estimated from measuring the local SW velocity.
There are multiple ways of generating SW using acoustic radiation force impulses. The purpose of this study was therefore to
compare the performance of four different pushing sequences with a commercial device and in an experimental setup.
2. Methods
A programmable ultrasound system (Verasonics Inc, Redmond, WA, USA) with a 128-element linear transducer (Philips L74) was used to induce SW in a homogeneous PVA phantom (10% PVA, 3% graphite, 2 freeze cycles) and to measure the
SW propagation. 180V p-p voltage and 5 MHz centre frequency were used for each transmission. Four pushing sequences
were investigated: 1) focused push, focusing at a single point for 96 μs, 2) unfocused push, where the 12 central elements
were excited for 198 μs to generate an unfocused plane wave, 3) unfocused comb-push [1], where four simultaneous and
unfocused pulses, equally spaced in the lateral direction, were emitted, and 4) line-push [2], where three pushes were focused
along a line at progressively deeper focal points. The focused pushes were spaced 0.7 mm axially with a 0.2 ms delay
between pushes.
SW propagation was imaged with plane wave pulses at a frame rate of 10 kHz and 5 MHz centre frequency. The average of
three angled plane waves (-8º, 0º, 8º) was used to construct each frame. Axial particle velocity was estimated at each pixel
and frame using Loupas’ 2D autocorrelator [3] setting a 5-sample range gate length across 5 frames. The result was
directionally filtered to reduce noise and artefacts. By cross-correlating the time-dependent axial velocity of two pixels, 2 mm
apart laterally, the local SW speed was estimated (Figure 1). Due to the absence of SW in the pushing region, all
implemented sequences, apart from the comb-push, exhibit blind areas, in which SW speed cannot be estimated. The width
of this area was also measured. Finally, our implementations were compared with the commercial SW system Aixplorer
(Supersonic Imagine, France).
Figure 1: Directionally filtered axial velocity of SW generated by the four pushing sequences, at one depth.
3. Results
Table 1 summarizes the measured SW velocity and blind area width for each implementation. As can be seen, SW velocity
mean values are close to each other and to those obtained with the commercial system. The line-push resulted in the widest
blind area, while the comb-push had none.
Table 1: Measurement results for different pushing sequences.
SW velocity
Width of blind area
Unfocused
4.39 ± 0.18 m/s
2.3 mm
Comb-push
4.40 ± 0.21 m/s
0 mm
Focused
4.65 ± 0.29 m/s
2.5 mm
Line push
4.57 ± 0.30 m/s
3.0 mm
Aixplorer
4.5 ± 1.5 m/s
-
4. Conclusions
To summarize, all the pushing sequences implemented in this study performed similarly concerning the SW speed
estimation, with values close to the ones obtained with the commercial SW system. The comb-push, however, had the
advantage of not leading to any blind areas. Further investigations should include quality measures relevant to specific
clinical applications.
References
[1] Zhao, Heng, Pengfei Song, Matthew W Urban, James F Greenleaf, and Shigao Chen. “Shear Wave Speed Measurement Using an
Unfocused Ultrasound Beam.” Ultrasound in Medicine & Biology 38, no. 9 (September 2012): 1646–1655.
[2] Bercoff, J., M. Tanter, and M. Fink. “Supersonic Shear Imaging: a New Technique for Soft Tissue Elasticity Mapping.” IEEE
Transactions on Ultrasonics, Ferroelectrics and Frequency Control 51, no. 4 (April 2004): 396 –409.
[3] Loupas, T., J.T. Powers, and R.W. Gill. “An Axial Velocity Estimator for Ultrasound Blood Flow Imaging, Based on a Full Evaluation of
the Doppler Equation by Means of a Two-dimensional Autocorrelation Approach.” IEEE Transactions on Ultrasonics, Ferroelectrics and
Frequency Control 42, no. 4 (July 1995): 672–688
80
3G6
AN INTELLIGENT PHONOCARDIOGRAM FOR AORTIC STENOSIS DIAGNOSIS
Arash Ghare Baghi1, Birgitta Janerot-Sjoberg2, Peter Hult, Per Ask1
Physiological measurement, Department of biomedical engineering, Linköping University, Linköping, Sweden
2 Departments of Clinical Science, Intervention and Technology, Karolinska Institutet & Clinical Physiology, Karolinska University
Hospital, Stockholm, Sweden
1
1. Introduction
“Cardiovascular diseases” is still the main factor of human mortality. A large percentage (as many as 70%) of the paediatric
referrals to the hospital for cardiac examinations, have normal hearts while to a lesser extent a number of pathological
patients are neglected by the screening procedures in primary healthcare centres [1]. The intelligent phonocardiogram is a
non-invasive, powerful and inexpensive approach which can serve as a screening tool in hands of the practitioners or nurses
in primary healthcare centres to select appropriate patients to undergo echocardiography which is by far a more expensive
approach. Studies showed that a computer assisted phonocardiography will substantially improve the screening accuracy [2].
Heart has a rhythmic mechanical action by which blood is pumped through the circulatory system. The mechanical action
constituted from the heart muscle movements and thereby opening and closure of heart valves. Phonocardiogram is an
acoustical recording of the heart sounds associated with the mechanical action. Auscultation of these sounds is still the main
technique for screening heart disease in the primary healthcare centres. However, the accuracy of this technique is influenced
by physiological restrictions exist in the human auditory system as well as other psychological and environmental effects.
Intelligent phonocardiogram is indeed a computer based stethoscope, supported by the intelligent algorithms to analyse heart
sound signal in order to detect pathological symptoms of the heart sound. As the aforementioned negative effects are
efficiently attenuated thanks to the rapid progresses in electronics systems and artificial intelligence, the undesirable factors
would be decreased in favour of the intelligent stethoscope. This device helps the practitioners or nurses in the primary
healthcare centres as a decision support or even as a screening tool. The powerful algorithms could be incorporated into
smart phones or tablets for automatic diagnosis to be used as a home healthcare system.
2. Method
Phonocardiogram signals were collected from the patients diagnoses as normal patients (30 cases) and the patients with aortic
stenosis (30 cases) according to the echocardiography. An electronic stethoscope which is commercially available was
utilized for signal recording. Data recording was done according to the guidelines of the corresponding hospitals which were
in compliance with the declaration of Helsinki. Patients gave their informed consents prior to the data recording. The study
was approved by the corresponding local committees. In this study, signal processing techniques in conjunction with our
innovative pattern recognition methods are employed to screen and diagnose Aortic stenosis in children and elderly people,
respectively. In order to evaluate the screening performance, random repeated sub sampling (RRSS) method is applied to
estimate an expected value for the three performance measures; classification rate, sensitivity and specificity.
3. Results
Balanced RRSS with 50%/50% of training/testing data is employed to evaluate the performance of the system. The average
values for accuracy, sensitivity and specificity after 50 iterations are estimated as 88%, 86% and 89% respectively.
Regression analysis confirmed the significance of the diagnosis with R>0.81.
4. Discussion
Results showed that the proposed system can act as an efficient tool for screening and diagnosis of aortic stenosis. It is
evidenced by the previous studies that the screening accuracy of a specialized cardiologist who relies on auscultation is about
80% [2], while the corresponding value of the intelligent phonocardiogram described is 88%. As a consequence, the
performance of the system in screening is at least as good as a specialized cardiologist and may, when tuned to a larger
database including greater variety of different heart conditions, it has potential to further improve frugal performance
availability e.g. in smartphones.
References
[1] C. G. DeGroff, S. Bhatikar, J. Hertzberg, R. Shandas, L. Valdes-Cruz and R. L. Mahajan, "Artificial neural networkbased methods of screening heart murmurs in children," Circulation, vol. 103, pp. 2711-2716, 2001.
[2] R. L. Watrous, R. W. Thompson and S. J. Ackeman, "The Impact of Computer-assisted Auscultation on Physician
Referrals Asymptomatic Patients with Heart Murmurs," Clinical Cardiology, vol. 31, pp. 79-83, 2008.
81
81
3G7
ULTRASOUND CONTRAST AGENT LOADED WITH NITRIC OXIDE AS A THERANOSTIC
MICRODEVISE FOR MYOCARDIAL ISCHEMIA.
Grishenkov D.1, Gonon A.2, Paradossi G.3, Janerot-Sjoberg B.1,2
Karolinska Institutet, Department of Clinical Science, Intervention and Technology: Medical Imaging and Technology, Stockholm, Sweden.
2
Karolinska University Hospital: Department of Clinical Physiology, Stockholm, Sweden
3
Università di Roma Tor Vergata, Diapartimento di Chimica, Rome, Italy
1
Introduction
Cardiovascular disease (CVD) accounts for 1/3 of total global deaths worldwide. The most widespread CVD is ischemic
heart disease. It is the leading cause of death in both genders, equally diagnosed in developed and developing countries with
mortality exponentially increasing with age. Efforts of healthcare system should be primary focused on prevention, timely
detection, efficient differentiation and instant treatment of the disease.
Method
Current project introduces a new class of microdevices providing integrated diagnostic and therapeutic applications, i.e.
theranostics, of ischemic heart disease using novel multifunctional polymer-shelled microbubbles (MBs) loaded with nitric
oxide (NO). We use a gas filled MBs with an average diameter of 3 µm stabilized by a biocompatible poly-vinyl-alcohol
(PVA) shell (see Figure 1). A gas core makes MBs an efficient ultrasound contrast agent. Substituting the core gas with a
therapeutic gas, in our case NO, opens new possibilities for local, specific drug delivery triggered by ultrasound.
Results and Discussion
A fabrication protocol of air-filled polymer shelled contrast agent has been developed. Polymer shelled MBs can be obtained
with different average sizes, and shell thicknesses depending on the pH and temperature of the master solution. The external
mean diameter changed from 2.0 ± 0.3 µm to 4.4 ± 1.1 µm, when the temperature was increased from 4 °C to 37 C°. Shell
thickness increased from 0.4 ± 0.1 µm to 0.6 ± 0.1 µm when pH was decreased from 5 to 2. Polydispersity and size
distribution can be further controlled by sizing the homogenizer’s tips. Particles' dimension should be not larger than the
capillary lumen, i.e. about 5 µm, and not smaller than hundreds of nanometres in order to avoid nanospecific effects such as
potential immune effects. MBs with narrow size distribution, i.e. monodisperse suspension, have unique resonance frequency
of oscillation. Acoustic insonation at a frequency close to the resonance generate strong nonlinear harmonic response, which
can be specifically discriminated in the received echo.
In vitro ultrasound tests showed an enhancement of the backscattered power (25±1 dB), comparable to the soft tissue
attenuation coefficients (0.8±0.04 dB/cm MHz) and phase velocities (1519±2 m/s). Assessment of the pressure threshold,
Pthr, at which the MBs shell fractures suggests that fatigue, i.e. accumulation of damage within the shell, is a physical
mechanism responsible for the fracturing process. A decrease of Pthr from 1.2±0.09 MPa to 0.9±0.05 MPa is obtained when
the number of cycles in the pulse increases from 6 to 12. Worth noting that below Pthr MBs can be imaged non-destructively
using second or super harmonic techniques and above Pthr destruction/replenishment algorithm offers the possibility to study
tissue perfusion and delivery therapeutic payload.
The cell viability tests performed so far indicate that polymer MBs are biocompatible but that there is an apparent
immune system response after 8 hours after accumulation especially in macrophages..
A preliminary protocol for NO loading of MBs has been developed. NO-gas, can be incorporated in the MBs by exposing
freeze-dried MBs to NO atmosphere in a pressure chamber. The re-dispersed MBs release NO during about 2 hours. In vitro
studies have shown that these NO loaded MBs are able to stop the clot formation. Ex vivo tests reveal that cardioprotection
mediation via NO is plausible and depends on intact NO-syntase. Potentially e.g. unstable plaques and reperfusion injuries
due to NO-syntase depletion can be treated with local NO delivery, thereby avoiding hazardous systemic effects.
Conclusion
We describe a polymer-shelled gas-core MBs that can be manufactured according to clinical requirements of controlled
size below 5 µm and narrow size distribution. They are chemically and mechanically stable, provide adequate acoustic
enhancement and can be loaded with NO for local and specific therapy. The plain MBs are biocompatible but alert immune
system response after 8 hours which has to be verified after NO-loading. A single injection of the proposed multifunctional
contrast agent together with ultrasound exposure has the potential to combine initial diagnostics, with treatment and
terapeutic monitoring.
Figure 1. Left: Schematic representation of PVA MB. Right: Electron micrograph of freeze-fractured MB showing a shell
thickness of about 200 nm with a microstructure of PVA microfibrils
82
Sammanfattningar
POSTERS
P1-P25
Moderator: Göran Salerud
83
P1
Quantitative Analysis of Aortic 4D Flow MRI: Reproducibility and Correlation with Growth
1
Petter Dyverfeldt1,2, Michael D. Hope2, Monica Sigovan2,3, Jarrett Wrenn2, David Saloner2
2
3
Linköping University, Linköping, Sweden. University of California San Francisco, CA, United States. University of Lyon, Lyon, France
Introduction
3D cine phase-contrast magnetic resonance imaging (“4D Flow MRI”) permits quantitative assessment of anomalous
alterations of aortic blood flow. Two hemodynamic parameters that have been used for this purpose is the wall shear stress
(WSS), which is known to regulate endothelial cell function, and the normalized flow displacement from the vessel center,
which was recently shown to correlate with increased growth rates of ascending aortic dilation [1,2]. Analysis of these
hemodynamic parameters requires that a user 1) positions a 2D plane of interest in the volumetric dataset and 2) delineates
the contour of the vascular lumen in this 2D plane. We set out to assess the reproducibility of 4D Flow MRI-based estimation
of WSS and normalized flow displacement at these two critical levels of user-interaction. Furthermore, we assessed which of
the parameters correlate best with aortic growth.
Materials and Methods
25 patients previously studied with 4D Flow
imaging were included. Previously reported
data on interval aortic growth was available for
each subject [2].
CMR velocity data from a plane perpendicular
to the ascending aorta just distal to the
sinotubular
junction
was
collected
independently by two blinded reviewers, and
then separately segmented by two blinded
observers (see Figure 1). Subsequently, the
following
parameters
were
calculated:
normalized flow displacement, maximum
peak-systolic WSS, maximum of systoleaveraged WSS, mean peak-systolic WSS,
minimal peak-systolic WSS. Normalized flow
displacement, which estimates the degree of
flow eccentricity, was calculated as in ref [1].
WSS calculation was performed with propriety
software (Flow Tool) [4]. Reproducibility
analysis and correlation with interval aortic
growth were performed.
Figure 1: Example case demonstrating the reproducibility analysis
performed in the present study. An isosurface of the thoracic aorta is
provided on the left to show the location of the planes selected
independently by two observers (one in red, the other in yellow). Each
plane was then independently segmented by two separate observers for
quantification of CMR hemodynamics parameters (one contour in
purple, the other in green). Normalized flow displacement from the
vessel center (blue circle) is depicted for each of the planes.
Results
Inter-observer correlations with regards to plane selection and contour delineation are reported in Table 1. For the contour
delineation, correlation coefficients were 0.97-0.98 for normalized displacement and 0.78-0.96 for the WSS parameters. For
the plane positioning, these correlation coefficients were 0.91-0.93 for normalized displacement and 0.47-0.85 for the WSS
parameters. Flow displacement best correlated with interval aortic growth (r = 0.65). The range of WSS parameters did not
correlate well with growth (r < 0.15).
Table1. Reproducibility analysis: inter-observer correlations
Observerplanes#1
versus
Observerplanes#2
Mean peaksystolic WSS
Max peaksystolic
WSS
Min peaksystolic
WSS
Max systoleaveraged WSS
Min systoleaveraged
WSS
Normalized Flow
Displacement
Contours #1
0.71
0.67
0.47
0.74
0.71
0.91
Contours #2
0.82
0.85
0.51
0.85
0.70
0.93
0.93
0.87
0.84
0.87
0.88
0.98
0.96
0.91
0.81
0.90
0.78
0.97
Observercontours#1 Planes #1
versus
Observercontours#2 Planes #2
Discussion
Normalized flow displacement is a reproducible hemodynamic marker that shows good correlation with interval aortic
growth. Reproducibility of contour delineation for WSS analysis was good and in line with previous reports [3]. However,
markedly lower reproducibility was found for the plane-positioning step of the WSS analysis. Normalized flow displacement
should be considered in future work aimed at identifying and risk-stratifying patients who are likely to develop clinically
significant aortic dilation based on MR-estimated hemodynamic parameters.
References: [1] Sigovan M, et al. JMRI 2011;34:1226-30. [2] Hope MD, et al. JACC 2012;60:356-7. [3] Markl M, et al.
JMRI 2011;33:988-94. [4] Stalder A, et al. MRM 2008;60:1218-31.
84
P2
ULTRASOUND SPECKLE TRACKING FOR ARTERIAL STRAIN IMAGING – A VALIDATION
STUDY IN-SILICO, IN-VITRO AND IN-VIVO
1,2
1
2
1
2
Matilda Larsson , Brecht Heyde , Lars-Åke Brodin , Jan D’hooge
KTH-Royal Institute of Technology, School of Technology and Health, Stockholm, Sweden.
2
Department of Cardiovascular Sciences, KU Leuven, Leuven, Belgium
1. Introduction
Ultrasound-based speckle tracking for estimation of arterial wall strain has potential to be used for assessment of arterial
stiffness to improve cardiovascular risk stratification. However, most speckle tracking algorithms have been developed and
validated for cardiac applications, whereas strain assessment in the artery wall is more challenging due to lower strain
amplitudes combined with poor spatial resolution. This project aimed to develop and test an ultrasound-based speckle
tracking algorithm for strain estimation of the artery wall in simulated data sets, in an experimental setup and in an animal
model.
2. Method
A speckle tracking algorithm tuned for the vascular setting was developed in Matlab (normalized cross-correlation for 2D
motion estimation across frames, kernel size: 5λ×2λ, axial and lateral kernel overlap: 40% and spline interpolation for subsample motion detection). Accumulation of the displacement maps throughout the cardiac cycle was performed and
longitudinal and radial strains were then obtained by linear regression after averaging in one direction of the selected region
of interest (radially for longitudinal strain and vice versa). The strain curves were then drift compensated and low-pass
filtered. The speckle tracking algorithm was validated in three steps: in-silico, in-vitro and in-vivo. First, it was applied on
simulated ultrasound images from a kinematic cylindrical model of the carotid artery with realistic dimensions and
movement pattern. The ultrasound images were simulated using a generalized convolution model (COLE) with realistic
image properties and the estimated strain was then compared with the ground truth from the model. In the experimental
validation, the algorithm was applied on ultrasound images from polyvinyl alcohol phantoms mimicking the carotid artery.
The phantoms were connected to a pulsatile pump, programmed to generate carotid flow profiles. Sonomicrometry crystals
were glued on the phantom walls and used to acquire reference values of strain. In the in-vivo validation, the algorithm was
applied on ultrasound images obtained in a sheep model. The left carotid arteries of 3 sheep were exposed during isofluran
anesthesia and two sonomicrometry crystals were sutured onto the artery wall to obtain reference values of longitudinal
strain. The wound was closed and filled with ultrasound gel followed by ultrasound imaging at baseline and stress.
3. Results
An overall good agreement was found between the strain estimated with the speckle tracking algorithm and the reference
strain in the three validation setups. In-silico, the peak systolic radial strain was estimated to be -13.15 ± 0.99% (ground truth
13.89%) while longitudinal strain was 5.25 ± 1.20% (ground truth 5.30%). The correlation between estimated mean peak
strain values and reference peak strain values was r = 0.92 (p < 0.001) for radial strain and r = 0.72 (p = 0.006) for
longitudinal strain in the experimental setup. The results from the in-vivo validation are shown in Fig. 1.
4. Discussion
This study shows the feasibility of estimating radial and longitudinal strain in the carotid artery using ultrasound speckle
tracking. However, the step from in-silico and in-vitro to in-vivo estimation is challenging and the surgical exposure in the
in-vivo validation may have affected the artery wall properties since lower strain values than previously observed in-vivo
were obtained. Moreover, further studies are needed to test the algorithm on human in-vivo data and to investigate the
potential of the method to estimate arterial stiffness and detect cardiovascular diseases at an early stage.
85
85
P3
Bioclearance of a novel polymer-shelled multimodal contrast agent
Malin Larsson1, Johan Härmark1, Anton Razuvajev 2, Kenneth Caidahl2, Anna Bjällmark1,2
1
Kungliga tekniska högskolan - STH, Stockholm, Sweden. 2 Karolinska institutet, Solna, Sweden
1. Introduction
Multimodal imaging is a promising approach in the diagnosis of various diseases. To increase the sensitivity and specificity
of modality fusion, contrast agents (CA) consisting of encapsulated microbubbles (MBs) supporting multimodality imaging
approaches would be of great value. A novel polymer-shelled CA with multimodality potential is currently under
development. This CA has physical properties which differ significantly from the presently used lipidic CAs such as a high
mechanical and chemical stability, facilitating a possible use of these MBs as carriers for different substances. Despite all
possible improvements, the bioclearance of the novel CA needs be investigated. The aim of this study was therefore to
investigate the blood circulation time and the elimination pathway of three different types of the novel CAs in a rat model
using ultrasound imaging and transmission electron microcopy (TEM).
2. Methods
Three types of the novel polymer-shelled CA were employed in the study; a plain polymer- shelled CA (Plain) useful solely
with ultrasound (US) imaging and two types with modified shell or shell surface, both containing superparamagnetic iron
oxide nanoparticles (SPIONs) for combined ultrasound and magnetic resonance imaging [1-2]. In one of the modified CA
(Type A), the SPIONs were covalently linked to the shell surface through chitosan molecules, whereas in the other modified
CA (Type B), the SPIONs were embedded in the shell. Moreover, SonoVue® was used as reference in the US experiments.
A bolus of 0.4 ml of the CAs listed in Table 1 was injected through the jugular vein. For animals analyzed with US, image
sequences of the carotid artery were acquired using a Vevo2100 system (f=18MHz, 15 frames/s) (FUJIFILM VisualSonics
Inc., Canada) in the nonlinear contrast mode. After completed experiments, the image sequences were exported to a
workstation for further analysis. A region of interest (ROI) was manually placed in the middle of the vessel lumen and the
mean intensity over time, within the ROI from each image sequences, was analyzed in Matlab (MathWorks, United States).
Before further processing, the obtained data was filtered using a convolution filter (1x8). In order to evaluate the wash-outtimes for the different CAs, normalized curves were approximated using the nonlinear last square method. In the other animal
group, tissue samples from liver, lung, spleen and kidney were collected at different time points and analyzed using TEM.
Table 1. The contrast agents and the number of animals included in the study.
Contrast agent
Histological analysis
Plain [7.5 x 107MBs/ml]
Type A [7.5 x 107MBs/ml]
Type B [7.5 x 107MBs/ml]
Plain [6.6 x 108MBs/ml]
Type A [6.6 x 108MBs/ml]
Type B [6.6 x 108MBs/ml]
SonoVue® [2-5 x 108MBs/ml]
*Two repeated injections
10 min
1
1
1
-
3. Results
A 50 % decrease in the peak enhancement was observed for all
CAs during the first 30-60 seconds, see Figure 1. Compared
with SonoVue®, the novel CAs had longer detectable
circulation time in the blood, where the longest circulation
time was observed for the Plain CA. An uptake of MBs in the
macrophages was observed in all tissue types for all CAs
investigated, see Figure 2. None of the CAs were located
outside the blood vessels, indicating no uptake in parenchymal
or endothelial cells for any types of tissues investigated.
Fragments of CAs were observed all every tissue sections,
regardless of time point and CA type.
40 min
1
1
1
-
Ultrasound
24 h
1
1
1
-
4*
4*
4*
4*
Figure 1: Wash-outtime-curve obtained for
SonoVue® blue curve,
Plain red curve, Type A
black curve and Type B
green curve.
4. Conclusions
The blood elimination time, determined when using ultrasound
imaging, indicated a longer elimination times for the novel
CAs compared with the commercially available CA SonoVue®.
The macrophages were suggested to be responsible for the
elimination processes.
Figure 2: Electron micrographs of Type A microbubbles found (A)
internalized in a rat liver Kupffer cell and (B) inside a rat lung capillary,
both obtained 10 min after injection.
References
[1] Brismar TB, et al., Magnetite Nanoparticles Can Be Coupled with Microbubbles to Support Multimodal Imaging.
Biomacromolecules 2012;13 (5):1390-9.
[2] Paradossi G, et al., Tailoring of physical and chemical properties of macro- and microhydrogels based on telechelic PVA.
Biomacromolecules 2002;3:1255-62.
86
P4
THE CARDIAC STATE DIAGRAM AS A NOVEL APPROACH FOR EVALUATION OF CARDIAC
TIME INTERVALS IN ACS PATIENTS.
1
1
2
Jonas Johnson , Carl Westholm
2
Department of Medical Engineering, School of Technology and Health, Royal Institute of Technology, Stockholm, Sweden. Department of
Cardiology, Karolinska University Hospital, Huddinge, Sweden.
ABSTRACT
The CSD method is based on a new model for how the heart performs its pump and regulatory functions [1,2]. This model
states that the heart pumps and auto-regulates the flow of blood according to the DAPP technology, which is a new type of
pump technology with very efficient pump characteristics.
The DAPP technology and therefore also the heart performs its functions optimally based on a dynamic process in the hearts
inflow, outflow and internal flow. Therefore the starting and end point of the different cardiac events and changes in dynamic
and static energy generated by the heart’s AV-plane (piston) movements transferred to pressure and flow into, inside and out
of the heart. This definition of cardiac phases is novel and does not coincide with the previously described phases since the
DAPP-technology has not previously been known.
1. Objective
To investigate cardiac time intervals using Tissue velocity imaging (TVI) echocardiography and generate a state diagram that
provides easily accessible overview of the cardiac state regarding timing events on the segmental level. We intended to
interrogate whether state diagram could differentiate ACS patients from healthy individuals.
2. Method
The study consisted of 197 consecutive ACS patients and a control group of 42 healthy individuals. TVI measurements were
done at the basal segment of the LV in the 3 apical planes. All analyses were performed off-line using EchoPac workstation.
All cardiac state diagrams were generated with the analysing software, GHLab. Statistical analysis was done with SPSS.
3. Results
The majority of the cardiac time intervals between events under investigation differ between healthy and non-healthy
individuals. The transition phases i.e. the pre- and post-ejection intervals were significantly prolonged in the ACS group
(p<0.001), using independent t-test.
4. Conclusion
Cardiac time intervals assessed by cardiac state diagrams (CSD) can differentiate ACS patients from healthy individuals. The
novel approach is feasible and may provide robust information for the differentiation between ACS and healthy individuals.
References
[1] Lundbäck, Stig, “Cardiac Pumping and Function of the ventricular Septum”, Acta Physiologica Scandinavica Supplementum, 1986
[2] Lundbäck, Stig, Heart Cluster State Machine Simulating the Heart US patent application 20080154142 (2005)
87
87
P5
THE CARDIAC STATE DIAGRAM AS A NOVEL APPROACH FOR EVALUATION OF PRE- AND
POST EJECTION PHASES OF THE CARDIAC CYCLE IN ASPHYXIATED FETAL LAMBS
1
2
1
3
3
2
2
Elle Wågström , Jonas Johnson , Kjerstin Ferm-Widlund , Nina Elmstedt , Karina Liuba , Britta Lind , Lars-Åke Brodin , Stig
4
1
Lundbäck , Magnus Westgren
1
2
Department of Obstetrics and Gynecology, Center of Fetal Medicine, Karolinska University Hospital, Stockholm, Sweden. Department of
3
Medical Engineering, School of Technology and Health, Royal Institute of Technology, Stockholm, Sweden. Department of Obstetrics and
4
Gynecology, Skåne University Hospital, Sweden. Gripping Heart AB, Stockholm, Sweden.
ABSTRACT
The CSD method is based on a new model for how the heart performs its pump and regulatory functions [1,2]. This model
states that the heart pumps and auto-regulates the flow of blood according to the DAPP technology, which is a new type of
pump technology with very efficient pump characteristics.
The DAPP technology and therefore also the heart performs its functions optimally based on a dynamic process in the hearts
inflow, outflow and internal flow. Therefore the starting and end point of the different cardiac events and changes in dynamic
and static energy generated by the heart’s AV-plane (piston) movements transferred to pressure and flow into, inside and out
of the heart. This definition of cardiac phases is novel and does not coincide with the previously described phases since the
DAPP-technology has not previously been known.
1. Objective
To investigate myocardial wall motion, using echocardiography and colour-coded tissue velocity imaging and generate
Cardiac State Diagram according to a recently new developed program for evaluation of the duration of the Pre- and Post
Ejection phases, in the cardiac cycle in asphyxiated fetal lambs.
2. Method
Six near term lambs were partly exteriorized and monitored using echocardiography and colour-coded tissue velocity
imaging while brought through asphyxia to cardiac arrest. Arterial blood sampling for lactate and blood gas measurements
were simultaneously performed, the first sample taken before cord occlusion and then every 5 min until cardiac arrest. The
heart’s mechanical function of the fetal lamb was evaluated in newly developed software GHLab based on the assumption
that the heart’s pumping and regulating functions acts according to a new pump-principle today recognized as the Dynamic
Adaptive Piston Pump principle. The results from the software are displayed in an easy to interpret Cardiac State Diagram.
3. Results
All fetal lambs showed a prolongation of the Pre- and Post Ejection phases at the same time when the most pronounced
change in lactate and pH occurred. The percentage change of the duration of the Pre- and Post Ejection phases were
significantly longer in all fetal lambs, 49% (p<0.001) and 38% (p<0.049) respectively. The heart’s mechanical function was
interpreted and visualized in a Cardiac State Diagram where the cardiac events are detected and displayed.
4. Conclusion
As asphyxia progresses in fetal lambs, the duration of the Pre- and Post Ejection phases increased and the Cardiac State
Diagram has the potential of being a comprehensible tool for detecting fetal asphyxia.
References
[1] Lundbäck, Stig, “Cardiac Pumping and Function of the ventricular Septum”, Acta Physiologica Scandinavica Supplementum, 1986
[2] Lundbäck, Stig, Heart Cluster State Machine Simulating the Heart US patent application 20080154142 (2005)
88
P6
NON-INVASIVE INTERVENTION PLANNING OF STENOTIC FLOWS USING SCALE-RESOLVED
IMAGE-BASED COMPUTATIONAL FLUID DYNAMICS
1
2
Magnus Andersson , Jonas Lantz , Matts Karlsson
1
1
2
Department of Management and Engineering, Linköping University, Sweden. Department of Sciences and Technology (ITN), and Center
for Medical Image Science and Visualization (CMIV), Linköping University, Sweden.
1. Introduction
Subject-specific hemodynamic is often associated with laminar flow characteristics, which favour turbulent blood flow as a
fruitful indicator for prediction of potential cardiovascular events. A typical example of this is the turbulent flow triggered by
an aortic coarctation, which if left untreated could result in a fatal outcome. The energy associated with this flow, the
turbulence kinetic energy (TKE), will feed on the main flow and consequently increase the heart workload in order to
maintain the peripheral blood flow. Today, the severity of these coarctations is typically estimated based on the pressure
gradient over the narrowed region using invasive catheters pre- and post-intervention, which could be time consuming,
expensive and/or handling dependent. Instead we propose here a first step toward and non-invasive intervention planning
framework guided by scale-resolved image-based computational fluid dynamics (CFD) to get estimates of these severities.
The motivation is to provide a TKE map for both the coarctation as well as a variety of possible post-intervention
configuration at different cardiac output (CO) as the body will respond to the geometrical change. The advantages using TKE
is that it can be measured using MRI [1] and also proven to have a good relation versus simulated data [2]. Thus, this
framework is not only predictable using simulation but can also be validated through post-intervention TKE measurement.
Stenotic area
increase
11%
17%
45%
Figure 1: Left: Patient specific aortic coarctation model, Right: Three different simulated balloon
dilatations at 11%, 17% and 45% area increase.
2. Method
The patient-specific data was acquired from a 1.5 T Philips Achieva MRI scanner, followed by a 3D level set segmentation
technique in order to obtain the geometry of the central vessels surrounding the coarctation, see the left configuration in
Figure 1. Flow boundary conditions were obtained using 2D through-plane phase-contrast MRI at the ascending and
descending aorta. The balloon dilatation, which is typically used in the intervention procedure, was mimicked using an
inflation simulation in ANSYS Mechanical. By altering a local transmural pressure profile and supports over the lumen
surface a wide range of different deformation outcomes where obtained, Figure 1 shows three examples where 11%, 17% and
45% stenotic area was achieved. A scale-resolving turbulence model, large eddy simulation (LES), was utilized in order to
resolve the significant turbulence scales and also to be able to capture the laminar-to-turbulent transition of the flow
sufficiently. The measured ascending flow data was applied as an inlet boundary condition whereas the neck distribution
used a power-law relation of the diameter and flow. The body will respond to this area increase and provide more flow
through the coarctation. To get more insight of this flow adaption influence on the TKE levels a physiological upper limit of
CO after intervention was simulated for each case. In this case we choose a 20% increase from the baseline CO.
3. Results and Discussion
Evaluating the result over a specific control volume indicated a highly non-linear relationship between each dilatation and the
amount of TKE. For the baseline flow some cases showed approximately the same amount of total TKE despite having a
substantial difference in cross-sectional area. For the flow adaption scenario some cases ended up above the baseline TKE,
which is not desirable. Moreover, increasing the dilatation further seems to converge the total TKE to a plateau. Thus, there
should exist an optimum where the degree of dilatation meets the lowest possible decrease of total TKE, further balloon
intervention may only induce unnecessary high stresses onto the vessel wall.
References
[1] P. Dyverfeldt, J. Kvitting, A. Sigfridsson, J. Engvall, A. Bolger and T. Ebbers, Assessment of fluctuating velocities in
disturbed cardiovascular blood flow: In vivo feasibility of generalized phase-contrast mri, JMRI 28, 655-663 (2008).
[2] J. Lantz, T. Ebbers, J. Engvall and M. Karlsson, Numerical and Experimental Assessment of Turbulent Kinetic Energy in
an Aortic Coarctation, In press (2013).
89
P7
ENKEL DIAGNOSTISK UTRUSTNING FÖR TELEMEDICIN APPLIKATION I U-LÄNDER
Sharin Ahmed1, Maurico Gatica1, Poorang Soleimani1, Armin Saljunovic1, Gunnar Nihlen2, Mannan Mridha2
1
Studenter, 2handledar, Skolan för Teknik och Hälsa, Kungliga Tekniska Högskolan, Stockholm, Sweden
1. Introduktion
En stor del av världens befolkning saknar tillgång till basic hälso- och sjukvård pga. brist på läkare/vårdpersonal och tekniska
resurser. Drygt 40 procent av sjukvårdsutrustningen i utvecklingsländerna fungerar inte tillfredställande. Det kan bero på att
utrustnigen är för avancerad och personalen får inte adekvat utbildning och det saknas välfungerande underhållsystem [ 1].
.Det är nödvändigt att utveckla lämpliga och kostnadseffektiva diagnostiska utrustningar och satsa på att öka användarnas
tekniska kompetens. Sedan många år har STH-KTH angagerat sig att utveckla telemedicin system för u-lands applikationer
där ingår: a) att ta fram robusta, batteridrivna och säkra diagnostiska utrustningar b) utveckla kommunikation mellan
patient/vårdpersonal och läkare via tillgänglig internetsystemet, c) att producera lämpliga utbildningsmaterial för
empowerment av vårdpersonal och patienter och på så sätt förbättra hälsovården och öka patientsäkerheten [ 2].
2. Metod
I det här arbetet, har en prototyp konstruerats för att på ett non-invasivt sätt övervaka vitala signaler från patient genom
användning av smarta sensorer. Den är lätthanterlig för användaren efter att denne har fått en kortare utbildning. Prototypen
används tillsammans med ett USB-oscilloskop och dator för att registrera, dokumentera, observera och kommunicera
patientdata till specialist läkare för behandlingsråd.
3. Resultat
En prototyp som registrerar EKG-signaler, det arteriella blodtrycket, blodflödet och andningen har tagits fram. Dessa
signaler kan registreras och sändas för fjärrdiagnostik. Sensorsystemet visar att det är möjligt att konstruera en pålitlig, och
kostnadseffektiv medicinteknisk apparat för registrering av patientdata som kan användas i ”low resource settings”.
Figur 1 Illustrationen visar hur prototypen ska användas. Patientdata överförs via ett USB-oscilloskop till en dator för att överföra till en
kvalificerad läkare för diagnostik och behandlingsråd.
Materialkostnaden för denna prototyp ligger väl under 1000. Jämförbara kommersiella utrustningar kostar cirka 8000 ke
4. Diskussion
Läkarna som har bedömt användbarhet har varit positiva och har gett förbättringsförslag. Komponentkostaderna kan sänkas
ytterligare. Den arteriella pulsregistreringen kan göras stabilare och EKG-registreringen kan förses med en kalibrerad
baslinje. Nya patient data presentationssystem kommer att presenteras på tex. Läsplatta.
Figur 2. En del av prototypens kretsschema.
Ovan visas kretsschema över pulsregistrering
Figur 3. Insidan av prototypen
Figur 4. Utsidan av prototypen
5. Referenser
[1] Peter Howitt, Donated medical equipment going unused in developing countries,
http://www.radioaustralia.net.au/international/radio/program/connect-asia/donated-medical-equipment-going-unused-indeveloping-countries/991886 14 maj 2013
[2] Mridha M.,Pehrson Björn (2004) To develop a telemedicine system to improve remote diagnoses and to deliver cost effective,
better quality specialist services in developing countries, International conference on Wide Open Access, Stockholm 2004
90
P8
Preliminary Results of Studying Bone Growth Using NaF-18 in Patients with a Taylor Spatial Frame
Henrik Lundblad1, Marilyn E. Noz2,Gerald Q. Maguire Jr.3, Cathrine Jonsson4, Hans Jacossson5, Anders Sundin1
Department of Molecular Medicine and Surgery, Karolinska Institute, Stockholm, Sweden 2Department of Radiology, New York University,
New York, NY 3School of Information and Computer Technology, KTH Royal Institute of Technology, Stockholm, Sweden 4Department of
Medical Physics Karolinska University Hospital, Stockholm, Sweden 5Department of Radiology, Karolinska University Hospital, Stockholm,
Sweden
1
1. Introduction
The aim of this study is to assess bone growth in patients who are undergoing treatment of the tibia by surgical application of
an Ilizarov derived Taylor Spatial Frame (TSF) (see Figure 1). This device is capable of simultaneously correcting
displacements of angulation, rotation, and translation. Use of this apparatus may be indicated due to prior bone disease
resulting in deformation, the need to lengthen one leg to match the other, or severe or malhealed fracture. We used a sodium
fluoride F-18 (NaF-18) PET/CT bone scan to detect actively growing bone[1]. Although a CT scan by itself can indicate
changes in bone, it cannot give an estimate of bone growth. Before beginning this study, we did a literature search to
determine the optimal amount of radioactive material to administer to the patient. Additionally, we investigated the impact of
the metallic reduction algorithm on the quantification of the PET scans by performing a phantom study in which a TSF was
affixed to a plastic tibia, both of which were partially submerged in a bath of 217 Mbq NaF-18. The results were presented at
the World Molecular Imaging Conference, Dublin, in September 2012. Proper positioning of the patient on the scanning
couch has also been studied and these results will be presented at the Society of Nuclear Medicine annual meeting in
Vancouver, Canada, June 2013. This study was approved by the Karolinska Hospital Ethics Committee North.
2. Method
Since September 2012, every tibia patient undergoing this TSF procedure was invited to join to the study. Thus far a total of
six (out of seven) patients have been studied. The study patients underwent a PET/CT scan (64 slice Siemens Biograph
TruePoint TrueV) at approximately six weeks and then again at three months after the application of the TSF. One scan bed
position was used (22 cm length). Administered activity was 2 Mbq per kilogram of body weight. A list mode acquisition
was done for 45 minutes and a five minute static scan was acquired after 60 minutes. Additionally, two patients who were
very close to having the TSF removed agreed to have a clinical PET/CT scan for comparison with the initial bone growth
patients and to help determine if the state of their bone permitted removal of the device. We evaluated bone activity by using
the standard uptake value (SUV). We matched the CT scans from the longitudinal studies in order to ensure that we evaluated
the SUV at the same position in the bone for both studies. For this registration, we used a software tool that has been
previously described and validated [2-4].
3. Results
In one patient, we detected that the fibula had an SUV max of 65 while the tibia had an SUV max of 8, thus indicating that the
fibula was growing much faster than the tibia as illustrated in Figure 2. The surgeon had to intervene, and re-break the fibula.
Three months after this, both bones were growing at approximately the same rate (with an SUV max of 35). One patient moved
one leg between the CT scan and PET scan (see Figure 3), and thus image registration had to be performed to do the
evaluation. We have obtained SUV values for all the studied patients, but no statistically valid estimate can be made from this
preliminary data.
4. Discussion
This study leads to a number of clinical questions that could be usefully answered. One question is: When has the bone
healed well enough that the TSF can be removed without a high probability of the bone re-breaking? Another question is if
there is some correlation with a non-imaging modality - especially for the clinical decision to remove the TSF; e,g., could a
NaI probe over an area be used or some other naturally occurring tracer be evaluated. Further, could a provocation technique
using a piezo-electric transducer be used as an external pressure transducer for external load to (a) assess bone growth and (b)
encourage bone growth as part of the therapy. We hope to answer some of these questions as our study progresses.
References
[1] F.D. Grant, F.H. Fahey, A.B. Packard, R.T. Davis, A. Alavi,S.T. Treves, J Nucl. Med 49, 68-78 (2008).
[2] M.E. Noz, G.Q. Maguire Jr, M.P. Zeleznik, E.L. Kramer, F. Mahmoud, J. Craford J. J Med Syst 25, 297–307 (2001).
[3] L. Olivecrona, J. Crafoord, H. Olivecrona, M.E. Noz, G.Q. Maguire Jr, M.P. Zeleznik, L. Svensson, L. Weidenhielm
Acta Radiol 43, 517–27 (202).
[4] R.J.T. Gorniak, E.L. Kramer, G. Q. Maguire Jr, M.E. Noz, C.J. Schettino, M.P. Zeleznik, J Med Syst 27, 141–56 (2003).
Figure 1: Taylor Spatial Frame
91
Figure 2: Accelerated Bone Growth
Figure 3: Mismatched PET/CT
P9
ON THE FULLY AUTOMATIC CONSTRUCTION OF A REALISTIC HEAD MODEL FOR EEG
SOURCE LOCALIZATION
Qaiser Mahmood,1 Yazdan Shirvany,1 Andrew Mehnert,1 Artur Chodorowski,1 Johanna Gellermann,2 Fredrik Edelvik,3 Anders
Hedström,4 Mikael Persson1
1
Department of Signals and Systems, Chalmers University of Technology and MedTech West Center, Göteborg, Sweden, 2Universitätsklinik
für Radioonkologie, Tübingen, Germany, 3 Fraunhofer-Chalmers Research Center, Chalmers Science Park, Göteborg, Sweden, 4Sahlgrenska
Academy, Göteborg, Sweden.
1. Introduction
Accurate multi-tissue segmentation of magnetic resonance (MR) images is an essential first step in the construction of a
realistic finite element head conductivity model for electroencephalography (EEG) source localization. All of the
segmentation approaches proposed to date for this purpose require manual intervention or correction and are thus laborious,
time-consuming, and subjective.
2. Method
We propose and evaluate a fully automatic method based on a hierarchical segmentation approach (HSA) incorporating
Bayesian-based adaptive mean-shift segmentation (BAMS).
3. Results
An evaluation of HSA-BAMS, as well as reference method HSA-HMRF-EM, in terms of both segmentation accuracy and the
source localization accuracy of the resulting finite element head conductivity model is also presented. The evaluation was
performed using real 3D T1-weighted MRI head data and real EEG data (with expert determined source localization).
Tissue
HSA-BAMS
HSA-HMRF-EM
WM
GM
CSF
0.885
0.848
0.523
0.879
0.836
0.517
Skin
Skull/
Bone
0.868
0.697
0.822
0.588
Methods
21.0mm
25.0mm
TABLE III. LOCALIZATION ERROR
0.35
HSA-HMRF-EM
0.42
Ground truth
0.23
Table II. RELATIVE ERROR FOR EACH METHOD
Table I. Dice Index Values for Each Method and Each Tissue
Methods
HSA-BAMS
HSA-HMRF-EM
HSA-BAMS
22.0o
24.0o
AND ORIENTATION ERROR
4. Discussion
The results demonstrate the efficacy and accuracy of the method, that it outperforms the reference method, and suggest that it
can be used as a surrogate for manual segmentation for the construction of a realistic finite element head conductivity model
for EEG source localization.
References
[1] M. Rullmann , A. Anwander, M. Dannhauer, S. K. Warfield, F. H. Duffy, C. H. Wolters, “Source EEG source analysis of
epileptiform activity using a 1 mm anisotropic hexahedra finite element head model,’’ Neuroimage, 44, 399-410 ( 2009).
[2] C. H. Wolters, A. Anwander, X. Tricoche, D. Weinstein, M. A. Koch, R. S. MacLeod “Influence of tissue conductivity
anisotropy on EEG/MEG field and return current computation in a realistic head model: a simulation and visualization study
using high-resolution finite element modeling,” Neuroimage, 30, 813-26 (2006).
[3] A. Mayer, H. Greenspan, “An adaptive mean-shift framework for MRI brain segmentation,” IEEE Trans. Med. Imag., 28,
1238–1249 (2009).
92
P10
Invitro toxicity testing utilizing microfluidic affinity biosensors
Invitro toxicity testing utilizing cell lineages such as hepatic cells, cardiac cells and neuronal cells is an
important tool for drug toxicity evaluation in the pharmaceutical industry. Micro-culture systems
have the benefit of reducing both quantity of cells and pharmaceutical candidate needed for testing.
A micro-culture system must be combined with a rapid and sensitive assay method capable of
analysing small amounts of sample. Detection of the toxicity response is often carried out by affinity
methods like SPR and ELISA, colorimetric assays using imaging systems or electrochemical methods.
New findings will be pre presented on the above mentioned systems. We present a strategy for
toxicity testing in a microfluidic culturing system where affinity biosensing and colorimetry are used
as endpoint assays.
93
P11
HEART RATE VARIABILITY (HRV) IN PATIENTS WITH CHRONIC KIDNEY DISASES
Farhad Abtahi1, Marie Hilderman2, Fernando Seoane1, 4, Annette Bruchfeld 2 and Kaj Lindecrantz1, 3
School of Technology and Health, KTH Royal Institute of Technology, Stockholm, Sweden, 2 Renal Medicine, CLINTEC, Karolinska
Institute, Stockholm, Sweden, 3Department of Clinical Science, Intervention and Technology, Karolinska Institute, Stockholm, Sweden.
4
School of Engineering, University of Borås, Borås, Sweden
1
1. Introduction
Loss of renal function is a disorder that can strike acutely or develop progressively. The most common causes of slowly
developing chronic kidney disease (CKD) are diabetes mellitus, chronic glomerulonephritis and hypertension. Advanced
CKD often involves a number of complications such as disturbances in the autonomic nervous system and inflammation. The
inflammation is often associated with autonomous nervous dysfunction quite common in these patients, since the central
nervous system partly controls the immune system through the cholinergic anti-inflammatory pathway (CAP) [1]. This
pathway functions as a nerve-mediated reflex that in case if injury, inflammation or infection send signals to the brain via the
vagus nerve. Since HRV analysis is a common tool for assessment of autonomic nervous system, this study wishes to
monitor autonomic dysfunction in patients with kidney diseases through HRV and respiratory measurements and try to find a
potential correlation with inflammation markers in blood.
2. Method
Twelve patients; seven in chronic haemodialysis (four male, three female; age range 26-84), five in peritonealdialysis (3
male, 2 female; age 47-84) and eight healthy control subjects (five male, three female; age 31-52) are included in this study.
Electrocardiogram (ECG) and tetrapolar thoracic bioimpedance are measured using custom made instrument designed by ZHealth Technologies AB during 20 minutes. Subjects are assessed during morning hours at department of renal medicine in
Karolinska Hospital (Huddinge) in a lying down position. C-reactive protein (CRP) levels and other blood markers were also
measured to evaluate presence of inflammation. The RR interval variability (RRV) is automatically calculated based on
traditional derivate-based algorithm, introduced by Jiapu Pan [6]. Artifacts and ectopic beats are detected visually and are
removed. Frequency and time domain parameters such as LF, HF, LF/HF-ratio, SDNN, RMSSD, and pNN50 were extracted
and compared between different groups of study population. Thoracic bioimpedance measurements are used to calculate
respiration rate and check for effect of rhythmic heart rate variability (sinus arrhythmia) in calculated frequency domain
parameters. HRV analysis had done according to European Tack Force for HRV measurements [3].
3. Results
The preliminary result of spectral analysis of HRV is depicted in Figure 1 by HF and LF parameters. It is obvious that there
is a general reduction in both LF and HF power of HRV of patients compare to controls. The only patient with very high
HRV can be considered as outlier and exclude from results.
4. Conclusion
The preliminary results suggest that dialysis patients despite autonomic dysfunction which can cause systematic
inflammation as well. Further analysis of recordings is now undergoing to see possible correlation between blood markers
such as CPR with HRV parameters.
References
[1] Oke, Stacey L., and Kevin J. Tracey. "From CNI-1493 to the immunological homunculus: physiology of the
inflammatory reflex." Journal of leukocyte biology 83.3 (2008): 512-517.
[2] J. Pan, W. Tompkins, A real-time qrs detection algorithm, Biomedical Engineering, IEEE Transactions on (3) (1985)
230–236.
[3] Camm, A. John, et al. "Heart rate variability: standards of measurement, physiological interpretation and clinical use,
Task Force of the European Society of Cardiology and the North American Society of Pacing and
Electrophysiology." Circulation 93.5 (1996): 1043-1065.
Figure 1: Example of frequency domain analysis of HRV for controls and patient groups are illustrated by using HF (Y axis)
vs. LF (X axis).
94
P12
CARENET: AN INFRASTRUCTURE FOR HOME-BASED HEALTHCARE SERVICES
1
1
1
1
1
1
2
2
Voravit Tanyingyong , M. Siraj Rathore , Markus Hidell , Peter Sjödin , Björn Pehrson , Sven Jonsson , Kristina Groth
2
KTH Royal Institute of Technology, Stockholm, Sweden. Utveckling och Innovation, Karolinska Universitetssjukhuset, Stockholm, Sweden
1. Introduction
Healthcare services are usually high cost due to several factors such as the scarcity of high-skill medical practitioners,
demanding logistics, and costly proprietary equipment and infrastructure. Home-based healthcare is an attractive alternative
to reduce the cost. It also offers several advantages. For instance, it increases patient safety by enabling faster contact with
caregivers and reduces the number of trips the patients need to get to the hospitals.
Technologies can be used to extend the reach of healthcare services over the data network to virtually anywhere. Given the
advancement in today's technologies, such healthcare services can be delivered competitively with open source solution on
Commodity-Off-The-Shelf (COTS) hardware at a fraction of the cost.
This work is carried out as a part of Carenet [1], a multi-stakeholder initiative to provide healthcare services to patients at
their homes by allowing patients to interact and exchange medical data with doctors in realtime. Example use cases are
elderly people and prematurely born babies who might require special care and attention in case of an abnormal event occurs.
2. Methods
For the technical solution of the system, we propose Carenet architecture design based on open source solution on COTS
hardware. The prototype architecture is developed using a residential gateway (RG) that enables healthcare extension from
hospital to the patient's home in a robust, secure, and cost-effective manner. The design comprises of three parts; the RG
hardware design suitable for home environment with low cost, noise, and power consumption, the services with security and
guaranteed resources, and the resilient communication between home and hospital through multihoming to ISP.
We consider three services in our work. These services include high definition video conferencing (HDVC), sensor
monitoring, and patient records. The doctor can examine patients through HDVC and at the same time medical sensors such
as heart rate sensor can be used to collect real time medical data. The third service is the patient records, a database that
collects and provides medical history of a patient. The overview of the Carenet design is shown in Figure 1 (Left).
To demonstrate our system, we focus on the prematurely born babies use case [2]. We develop different scenarios based on
realistic situations derived from the home-care work flow process of the neonatal care unit in Karoliska university hospital in
Huddinge. Each scenario triggers different usage patterns of the system. We have personnel from the neonatal care unit try
out the system under different scenarios as shown in Figure 1 (Center) and (Right). After the trials, an individual interview
is carried out using a questionnaire with 36 questions related to functionality, usability, and presentation of the system.
3. Results and Discussion
According to the users’ feedback, the system is intuitive and easy to use. Although video conferencing can never replace all
physical home visits, our system demonstrates good potential. It is especially useful when it comes to assisting parents under
emergency situations as well as getting a second opinion from another medical practitioner. The results are promising and
motivate us to continue with technical and clinical studies in collaboration with the patient and family in the home.
Detail empirical studies on the technical solution are also carried out. Each of the three building blocks of our design is
evaluated independently. Power consumption and performance evaluation for the low power RG with resilient power sources
can be found in [3]. RG's isolation through Linux Containers is studied in [4]. Empirical results and analysis on resilient
communication through multihoming can be found in [5].
References
[1] Carenet-SE, http://www.carenet-se.se
[2] S. Jonsson, K. Groth, M. Blennow and H. Teriö, CARENET POC – neonatalvård mellan sjukhus och hem, Nov. 2012.
[3] A. Nungu, R. Olsson, and B. Pehrson, On the Design of Inclusive Ubiquitous Access, ICUFN 2011, pp. 288-293.
[4] N. Roumpoutsos, Virtualization Isolation Report v.1.0, Dec. 2012.
[5] V.Tanyingyong, M. S. Rathore, M. Hidell, and P. Sjödin, Resilient communication through multihoming for remote
healthcare applications, manuscript under review, 2013.
Figure 1: (Left) Carenet architecture design (Center) Trial scenarios – Hospital site (Right) Trial scenarios – Home site
95
P13
TEXTRODE BASED WEARABLE MEASURMENT SOLUTION FOR SKIN
CONDUCTANCE AND TEMPERATURE MEASUREMENTS
J Ferreira1,3, L Álvarez2, R Buendía1,2,3, D Ayllón2, C. Llerena2, R Gil-Pita2 and F Seoane1,3
1
School of Engineering, University of Borås, Sweden, 2 Department of Signal Theory and Communications, University of Alcala, Madrid,
Spain, 3 School of Technology and Health, Royal Institute of Technology, Stockholm, Sweden
E-mail: [email protected]
1.
Introduction
In the frame of the project “Real Time Assessment of Mental Stress of Soldiers During Combat”, with acronym ATREC
from its tittle in Spanish, several physiological signals were selected to find the most suitable way to detect stress in extreme
situations. 2 of the signals selected were the skin temperature and the skin conductance also named Galvanic Skin Response
(GSR). As GSR is the conductance measured between 2 points of the body, generally close to each other, it dramatically
increases with sweat. That means if the GSR is measured in a part of the body where the sweat is due more to psychological
stress than to physical effort, an increase in this signal might mean an increase in the stress of the subject. For that purpose 2
wearable measurement systems with smart textiles integrated for recording GSR in 2 different parts of the body were
developed. Those 2 parts are the tips of the fingers and the triceps as both were pointed out as places with little sweat due to
physical effort. Skin temperature measured in those 2 parts of the body might also be a stress indicator.
2.
The wearable measurement system
The reduced dimensions i.e. 50x35x15 mm, of the device to record GSR makes it suitable for its integration with the
sensorized garments. For the measurements of GSR a Wheatstone bridge topology with constant voltage excitation of 0.5 V
was used. The voltage is applied to the skin through a resistor of 2 kΩ that limits the maximum current. The Wheatstone
bridge differential voltage is measured by an instrumentation amplifier that it is connected to an Analog-to-Digital Converter
(ADC) input in the microcontroller in order to obtain the GSR value. The GSR is measured with a sampling frequency of 250
Hz. In addition it is battery operated with 900 mAh Lithium-Ion batteries, and is provided with an internal 4GB SD memory
card to allow long-term recordings and off-line analysis.
The first GSR measurement system consist of a glove with two textile electrodes integrated in the proximal phalanx of the
index and middle fingers on the inside of the glove for measuring the GSR. Also a temperature sensor has been placed in the
tip of the ring finger of the glove in order to sense the peripheral skin temperature, see Figure 1a for details. For the
temperature measurements a 1-wire digital thermometer DS1825 manufactured by Maxim Integrated has been used.
The second one is an upper arm strap with two textile electrodes integrated to sense the galvanic skin response in the skin
surface between the electrodes. A DS1825 sensor is also integrated in the inner lining of the strap in order to contact the skin
and this way measure the superficial skin temperature.
�
a)
b)
c)
d)
Figure 1: a) GSR and Temperature measurement places b) Glove for GSR and skin Temperature, b) representation of upper
arm strap and c) measuring unit and strap worn on the upper arm.
3.
Measurements
Skin temperature and GSR were recorded in several subjects. While skin temperatures produced very stable measurements
around 34 ºC with both garments producing flat recordings, GSR measurements exhibited larger variance, see Figure 2. Note
that the GSR data has been filtered with a moving average window of 5 seconds as in [1].
Figure 2: Galvanic skin response measurements. a) Glove, b) Upper arm strap
4.
Conclusion
The proper functioning of the implemented garments and devices allows us to conclude that the system is ready for the next
stage of this experimental phase: data recording in volunteers performing specifically design activities to cause stress.
5.
[1]
96
References
Shaomei, W.; Tao, L. In Exploring the use of physiology in adaptive game design, Consumer Electronics,
Communications and Networks (CECNet), 2011 International Conference on, 16-18 April 201, pp 1280-1283.
96
P14
TEXTRODE BASED WEARABLE MEASURMENT SOLUTION FOR ECG AND
THORACIC IMPEDANCE MEASUREMENTS
J Ferreira1,3, L Álvarez2, R Buendía1,2,3, D Ayllón2, C. Llerena2, R Gil-Pita2 and F Seoane1,3
1
School of Engineering, University of Borås, Sweden, 2 Department of Signal Theory and Communications, University of Alcala, Madrid,
Spain, 3 School of Technology and Health, Royal Institute of Technology, Stockholm, Sweden
E-mail: [email protected]
1.
Introduction
In the frame of the project “Real Time Assessment of Mental Stress of Soldiers During Combat”, with acronym ATREC
from its title in Spanish, several physiological signals were selected to research the most suitable way to detect stress in
extreme situations. 2 of them were Heart Rate (HR) and Respiration Rate (RR), which can be extracted from the
physiological measurements ECG and Thoracic Electric Bioimpedance (TEB). For that purpose a wearable measurement
system with smart textiles integrated which enable the measurement of ECG and TEB were developed.
2.
The wearable measurement system
The measurement device records both signals, ECG and TEB at a single frequency. The reduced dimensions of the device,
50x35x20 mm makes it suitable for its integration with the chest strap system. In addition it is battery operated with 900 mAh
Lithium-Ion batteries, and is provided with an internal 4GB SD memory card to allow long-term recordings and off-line
analysis. The intended use for this ECG/EBI device is to record cardiogenic biopotentials to compute the HR from the
obtained ECG and measure the impedance change caused during breathing to extract the RR from the recorded TEB signal.
The ECG signal is measured by a 1-lead instrumentation amplifier topology suggested by Merritt et al. in [1], the output
voltage is connected to an ADC input in the microcontroller and recorded with a sampling frequency of 250 Hz. The TEB
measurement is obtained using an excitation frequency of 50 kHz and a sampling frequency of 100 Hz. The impedance
estimation core is based on the SOC AD5933 manufactured by Analog Devices, implementing an analog front-end
customized for 4-electrode measurement [2].
A chest strap garment with repositionable textile electrodes to record 1-lead ECG from 2 textrodes and tetrapolar TEB
measurements with other 4 textrodes has been developed. The possibility of placing the electrodes in any place along the
horizontal and vertical straps enables the performance of different kinds of TEB measurements, see Figure 1. Depending on
the placement of the textrodes around the surface of the thorax and abdomen the TEB measurement will have more or less
cardiac and respiratory components allowing us to perform a multi-parametric signal recording if required.
Figure 1: Chest straps system confectioned for placement of ECG and TEB electrodes.
3.
Measurements
Surface cardiac biopotentials were recorded in several subjects with the wearable measurement system presented in Figure
1. As shown in Figure 2 the recording is fair, allowing for a straight detection of the R complex for heart rate assessment.
TEB recordings were obtained simultaneously to the ECG recording. The respiration activity is easily observable and thus
the RR easily extracted from the TEB signal.
Figure 2: (a) ECG recording. (b) Transthoracic Electrical Bioimpedance recording
4.
Conclusion
The proper functioning of the implemented garments and devices allows us to conclude that the system is ready for the next
stage of this experimental phase: data recording in volunteers performing specifically design activities to cause stress.
5.
[1]
[2]
97
References
Merritt, C. R.; Nagle, H. T.; Grant, E., Fabric-based active electrode design and fabrication for health monitoring
clothing. IEEE Trans Inf Technol Biomed. 2009, 274-80. doi: 10.1109/TITB.2009.2012408. Epub 2009 Jan 23.
Seoane, F.; Ferreira, J.; Sanchéz, J. J.; Bragós, R., Analog Front-End Enables Electrical Impedance Spectroscopy
System On-Chip for Biomedical Applications. Physiol. Meas. 2008, 29 S267-S278.
P15
E-health Dialysis: an Holistic Approach for a Telenephrology System
1
1
1
3
2
Fernando Seoane , Iván Pau , Javier Ferreira , Bodil Sjöberg Bengt Lindholm ,
School of Technology and Health, Royal Institute of Technology, Stockholm, Sweden
2
Baxter Novum, Karolinska institute, Stockholm, Sweden
3
Kungsholmendialyskliniken karolinska university hospital, Stockholm, Sweden
1
1. Introduction
One of the most resource requiring diseases is chronic kidney disease (CKD) with 10-12% of the population showing signs of
different stages of this disease. As the disease progresses patients develop end-stage renal disease (ESRD) requiring lifesaving renal replacement therapy (RRT) with dialysis or renal transplantation. Due to a worldwide increase in the prevalence
of obesity and DM, and the improved survival in patients with cardiovascular disease, the number of ESRD patients in the
world increases rapidly, and now exceeds 2.5 million.
In Sweden, almost 9,000 patients undergo RRT. About 80 % of the dialysis patients are being treated by hemodialysis (HD),
which for the majority of patients is performed in specialized centers, usually located in a hospital or in a dialysis clinic, three
times per week. A smaller number (< 5%) of the HD patients have self-care treatment at home (home HD, HHD) or at
limited care or self-care centers. About 20% of all dialysis patients are being treated by peritoneal dialysis (PD) performed by
the patients in their homes. Thus, home dialysis therapy by HHD or PD accounts for less than 25 % of all dialysis treatments
despite considerable economic and medical advantages.
In-center dialysis at the hospital or at specialized clinics produces a significant economic burden for society related not only
with the direct costs for dialysis treatment itself, especially for health care personnel, disposables, and capital costs for
buildings and equipment costs but also involves indirect costs associated with the management of patients such as and
transportation of patients to and from dialysis facilities three times per week.
The survival and quality of life of patients treated with dialysis at home is similar or better than center dialysis while the
direct and indirect socioeconomic costs are substantially lower. Dialysis at home does not only reduce cost for example
associated with less need of transportation but also improves the quality of life and well-being of patients. Thus increased use
of home dialysis would allow considerable costs savings and free up resources that that could be used for example for
management of other patients. Despite all the advantages associated with home dialysis, only 25% of the dialysis patients
chose this modality. We believe that the number of patients with such therapy could increase initially to comprise maybe
40%, or more, of all dialysis patients. This could be done with existing technologies; however, such a transformation would
be facilitated by improvements in specific areas such as in communication systems.
2. Objectives
This work presents an on-going project project that intends to implement a full e-health system that will enable a complete
paradigm shift in the care of CKD patient management thereby facilitating the intended increase of the number of patients
choosing the available homecare options. Increasing the proportion of home dialysis would have an enormous impact in all
aspects of point-of-care of these CKD patients.
In order to achieve such ´tele-nephrology system´ the system should comply with several requirements:
• The system should be user-centered from design to operation taking in to account the needs of the patients.
• A videoconference system should be available for performing tele-consultations.
• Dedicated home-monitoring equipment for blood pressure body fluid volume distribution assessment, including a
bioimpedance spectrometer and sensorized garments with textile electrodes.
• An efficient distribution system for the dialysis products and medications should ensure continuous functioning of the
home therapy.
• An IT platform integrating all the elements of the system ensuring, data collection, communication and visualization.
3. Current Status
A VINNOVA challenge driven innovation - initiation project has been granted. The partners’ consortium involving patients,
providers and clinicians is being built and at time of writing a fully functional existing prototype of a home monitoring
system based on bioimpedance technology and sensorized garments is being customized to fulfil the users’ requirements.
98
98
P16
RELEVANSEN AV BREST SPECIFIC GAMMA IMAGING (BSGI) SOM
KOMPLEMENT TILL RÖNTGENMAMMOGRAFI
1
1
Melker Hagelberg1, Victor Löf
Kungliga Tekniska Högskolan, Stockholm, Sweden.
1. Introduktion
I nuläget är Röntgenmammografi det första valet vid bröstcancerdiagnostik och har en genomgående sensitivitet på 78- 85 %.
Vid avbildning av tätare bröstvävnad sjunker sensitiviteten och specificiteten för Röntgenmammografi och antalet falskt
positiva resultat ökar, vilket leder till onödiga biopsier.
Under 1990-talet utvecklades Breast Specific Gamma Imaging (BSGI) [1]. BSGI är en organspecifik gammakamera
utvecklad för bröstavbildning. Tanken var att BSGI skulle komplettera Röntgenmammografi vid avbildning av tätare
bröstvävnad.
Studier från Palmedo et al. under 1990-talet visade att BSGI hade en sensitivitet och specificitet på 71 % respektive 69 %.
Fler studier visade att BSGI endast kunde avbilda palperbara tumörer [2]. Avbildning av palperbara tumörer gav ingen
diagnostiskt nytta och intresset för BSGI minskade. Detektorteknikerna för BSGI har utvecklas sedan 1990-talet och kommer
att fortsätta utvecklas. Det är därför av intresse att utreda vilka krav som ställs på en detektor för att BSGI ska vara relevant
som komplement till Röntgenmammografi. 2. Mål
Studiens mål är att ta fram en metod för att studera kraven på en detektors spatiala
upplösning och energiupplösning vid avbildning med BSGI för olika tumörstorlekar.
3. Metod
Metoden grundas i Monte Carlo simuleringar av BSGI i programvaran GATE: Figur
1. Realistiska simuleringar, med avseende på aktiviteter, aktivitetsupptagsförhållande
och detektoruppställning, framställs ifrån litteraturen inom området för BSGI. I
simuleringarna generas bilder för tumörstorlekarna fem och tio millimeter. Genom att
simulera kommer den spatiala upplösningen och energiupplösningen kunna varieras i
efterhand. Resultatet från variationen av upplösningen i bilderna tolkas kvantitativt
med Rose modellen. Den framtagna modellen kommer att kunna användas som en
plattform för fortsatta studier inom BSGI. Resultatet presenterades grafisk för varje
tumörstorlek med SNR som funktion av detektorernas spatiala upplösning och
energiupplösning.
Figur 1: Design i GATE
4. Slutsats
Den framtagna metoden kan användas för att på ett realistiskt och pålitligt sätt utreda vilka krav som ställs på en detektors
spatiala upplösning och energiupplösning vid avbildning av olika tumörstorlekar med BSGI. Vi har simulerat tumörer med
storlekarna fem respektive tio millimeter. Båda tumörstorlekarna var synliga i det spatiala upplösningsintervallet 0.1 till 5
mm och energiupplösningsintervallet 1 till 10 %, enligt Rose modellen. Resultaten visar på en optimal spatial upplösning
och energiupplösning för detektorn på två millimeter respektive 10 % för båda tumörstorlekarna: Figur 2.
Figur 2. Resultat av variation av upplösning.
5. Referenser
[1] Aktolun C, Bayhan H and Kir M, Clin Nucl Med, 17, 171-176 (1992).
[2] Khalkhali I, Villanueva-Meyer J, Edell S. L, Connolly J. L, Schnitt S. J, Baum J. K, Houlihan M. J, Jenkins R. M and
Haber S. B., Clin Nucl Med, 41, 1973-1980 (2001).
99
A PPB-LEVEL, MINIATURIZED AMPEROMETRIC NITRIC OXIDE SENSOR FOR
ASTHMA MONITORING
P17
Hithesh K Gatty1, S. Leijonmarck2, M. Antelius1, G. Stemme1 and N. Roxhed1
Microsystem Technology Lab, KTH Royal Institute of Technology, Stockholm, Sweden
2
Applied Electrochemistry, KTH Royal Institute of Technology, Stockholm, Sweden
1
This paper reports a novel miniaturized MEMS-based amperometric nitric oxide sensor that is suitable for a
point of care testing device for asthma. The novelty lies in the combination of a high surface area microporous
structured electrode, nanostructured Nafion that is coated on the side walls, and liquid electrolyte. This combination
allows detection of very low concentration (parts-per-billion) gas, has high sensitivity of 0.130 nA/ppb/cm2 and has
both response (t90) and recovery time of 6 s. The sensor is integrated with a PCB potentiostat to form a complete
measuring module.
Previous Work: Measurement of nitric oxide (NO) concentration in the range 0-100 ppb in exhaled breath is used
as a method for detection of inflammation in the airways of asthma patients [1]. Conventional electrochemical
sensors can detect 2-3 ppb gas concentration. However they suffer from long response time typically in the order of
60-100 s thus requiring complicated flow handling and buffered sampling of the gas. Most of the miniaturized NO
sensors are realized using metal oxide as the sensing material, but have limited detection range of 1-100 ppm [2].
Amperometric detection techniques using only solid polymer electrolyte (SPE) like Nafion has been shown to
detect NO [3-5] but the detection limit of 5 ppm is not useful for asthma detection.
This Work: We report a novel miniaturized MEMS-based amperometric nitric oxide sensor that has the required
performance for a portable asthma detector. The sensor is miniaturized with the surface area of only 0.27 cm2. It
uses a combination of thin (approx. 500 nm) nanostructured Nafion together with liquid electrolyte. This
combination gives it a response time of 6 s as opposed to conventional amperometric sensor, which has response
time typically in the order of 60-100 s. The sensor presented in this work has a sensitivity of 0.130 nA/ppb/cm2.
Experiments and Results: The working electrode of the NO sensor was fabricated according to the process
scheme illustrated in Figure 1. The counter and reference electrodes are fabricated on a 2 mm thick polycarbonate
sheet by evaporation of silver on one of the surfaces. The working electrode is glued with a spacer above the silver
electrodes using silicone adhesive. This set-up is then connected to a PCB based potentiostat forming the NO
sensing module as shown in Figures 2-4. The potential placed at the working electrode was +0.7 V vs. Ag/AgO2
reference electrode. At this potential the NO is oxidized, NO+2H2O → NO3- + 4H+ + 3e- . The sensitivity of the NO
sensor was measured to be 0.130 nA/ppb/cm2 with a detection limit in the ppb-range. The thin diffusion layer of
Nafion results in a response time of 6 s and makes the sensor potentially useful in breath analysis and point of care
testing for asthma. This work demonstrates the potential for miniaturized MEMS-based electrochemical gas sensors
with very high sensitivity and fast response time, enabling ubiquitous sensing in portable devices.
[1] T. Hemmingsson et al, J.Clinical Monitoring and Computing, (2004) 18:379-387.
[2] A. Afzal, et al, Sensors and Actuators B 171– 172 (2012) 25– 42
[3] P. Jacquinot, A.W. E. Hodgson, P. C. Hauser, Anal. Chim. Acta 2001, 443, 53.
[4] F. Opekar, K. Stulik, Anal. Chim. Acta 1999, 385, 151.
[5] F. Maseeh, M. J. Tierney, W. S. Chu, J. Joseph, H.-O. L. Kim,T. Otagawa, Transducers '91
Al2O3
Pt
Counter
Electrode
Working
Electrode
Reference
Electrode
NAFION
1cm
Si
Fig 1: Cross-section of the porous grid structure with Pt
deposition on the grid using atomic layer deposition (ALD).
Fig 3: Image showing the NO sensor on polycarbonate substrate
with electrolyte channel. Silver is evaporated on one of the
surfaces and is milled to demarcate counter and reference
electrode.
Si
Nafion
Al2O3
, Pt
Fig 2: SEM image showing close up of the cross section of
500nm thick nafion coated grid.
100
Fig 4: Plot of Nitric Oxide concentration vs. output current showing a
linear relationship. Each point in the graph shows one measurement
sample.
100
P18
NOVEL CHROMATIN TEXTURE FEATURES FOR THE CLASSIFICATION OF
PAP SMEARS
1
1
2
3
3
1,4
Babak Ehteshami Bejnordi , Ramin Moshavegh , K. Sujathan , Patrik Malm , Ewert Bengtsson , Andrew Mehnert
1
2
Department of Signals and Systems, Chalmers University of Technology, Gothenburg, Sweden. Regional Cancer Centre,
3
4
Thiruvananthapuram, India. Centre for Image Analysis, Uppsala, Sweden. MedTech West, Gothenburg, Sweden.
1. Introduction
The Papanicolaou or Pap test is the primary screening test for cervical cancer. One in every 10 to 20 positive cases is missed
in routine screening because of inappropriate interpretation and sampling error. Automation using a computer and robotic
microscope can address the first issue. Research suggests that malignancy-associated change (MAC) analysis can address the
second. MACs are subtle sub-visual changes in the appearance of normal-looking cells on an abnormal Pap slide. The MACs
features that have the most discriminatory power are those describing chromatin (stained DNA and associated proteins)
texture in the cell nuclei. We have developed a novel structural approach to the quantitative analysis of chromatin texture
[1,2,3].
2. Theory/method
Our approach is based on deriving features from an initial segmentation of the chromatin [2] in each nucleus into blob-like
texture primitives (see Figure 1). Our structural texture features [1,2,3] in essence describe the attributes and arrangement of
these resulting blobs. They fall into two broad categories: (i) statistics of morphometric features (size, shape, etc.) computed
for the blobs, and (ii) contextual features. The latter can be further subdivided into the following classes of features:
margination (blob distance to the nuclear boundary), clustering, blob features (e.g. proportion of nucleus occupied by dark
blobs), discrete texture features, and features derived from the Voronoi diagram and its associated graphs.
3. Experiments
The image data used originate from a set
of 68 conventional Pap smear slides. Each
was reviewed by a cytopathologist and
assigned a cytological diagnosis according
to the Bethesda system [4]. The
cytopathologist subsequently acquired
representative fields of view (FOVs) from
each slide. In the case of abnormal smears
this included FOVs with and without
diagnostic cells. The cytopathologist also
labelled individual cells in each FOV
accordingly. The FOV images were
acquired using a monochrome CCD
camera mounted on a light microscope
with a 40× objective lens. Each image has
Figure 1. The proposed structural texture features are derived from an initial
a grey-scale resolution of 8 bits per pixel
segmentation of the chromatin into blob-like primitives and their spatial
and is of size 1024×1344 pixels with
characterisation in terms of neighbourhood graphs associated with the
square pixels of size 0.25µm. To evaluate
Voronoi diagram.
the performance of the proposed
chromatin structural texture features two experiments were performed [1]. The aim of the first was to determine the most
discriminatory subset of features, from among the proposed features and a wide range of features drawn from the literature,
for discriminating between normal (NILM [4]) and abnormal (LSIL or HSIL) Pap smear slides. The aim of the second
experiment was to evaluate the performance of a variety of classifiers built using the features obtained in the first experiment
to discriminate between the normal and abnormal slides on the basis of only normal-appearing cells (i.e. excluding diagnostic
cells).
4. Results and discussion
The results of experiment 1, based on 159 features, show that a combination of our structural features and conventional
features yields a classification performance of 0.954 ± 0.019 (AUC ± SE) for the discrimination of normal (NILM) and
abnormal (LSIL and HSIL) slides [1]. The results of experiment 2, which considered only normal appearing cells from both
normal and abnormal slides, show (i) a classification performance of 0.822 ± 0.024, and (ii) that chromatin margination alone
yields a classification performance of 0.815 ± 0.019 [1]. Overall the results demonstrate the efficacy of the proposed
structural approach and that it is possible to detect MACs in Papanicolaou stain.
References
[1] B. E. Bejnordi, R. Moshavegh, K. Sujathan, P. Malm, E. Bengtsson and A. Mehnert, “Novel chromatin texture features
for the classification of Pap smears”, Proc. SPIE 8676, Medical Imaging 2013: Digital Pathology, vol. 867608 (2013).
[2] A. Mehnert, “Image analysis for the study of chromatin distribution in cell nuclei with application to cervical cancer
screening,” PhD Thesis, School of ITEE, The University of Queensland (2004).
[3] P. Jackway and A. Mehnert, “Chromatin segmentation”, United States Patent, no. 7574304 (11 August 2009).
[4] S. Diane, N., Ritu, R. Kurman, D. Davey and D. Wilbur, The Bethesda System for reporting cervical
cytology: Definitions, criteria, and explanatory notes, 2nd edition, New York, Springer (2004).
101
P19
ON-CHIP ACTUATION OF POLYMER SHELLED MICROBUBBLES
Satya. V.V.N. Kothapalli1, Muhammad Asim Faridi 1, Martin Wiklund1, Dmitry Grishenkov1
1
Royal Institute of Technology, KTH, Stockholm, Sweden
1. Introduction
Micro-sized gas bubbles (MBs) are used as a contrast agent for diagnostic ultrasound imaging as well as drug or gene
transfection due to their stable oscillation under ultrasound exposure [1]. The acoustically driven microfluidic chip is utilized
for cell/microparticle manipulations and cell-cell interactions [2]. The motion of thin protein/lipid shelled MBs are shown to
be controlled by acoustic standing wave in a bulk situation [3]. However, drug loaded thin shelled MBs are mechanically
unstable in the circulation. In contrast, having relatively stiff and thick shell polymer MBs offers increase stability both
mechanical and chemical [4]. As a result we focus on the study the interaction of thick shelled MBs and cells under
ultrasound exposure. The preliminary aim of this study is to observe the acoustical behaviour of thick polymer shelled MBs
in a microfluidic chip.
2. Method
A 4 cm long microfluidic chip (GeSim GmbH, Dresden, Germany) containing two rectangular and two oval sono-cages of
varying geometries was utilized. A 4×7 mm PZT piezoceramic element was glued on one sided of microfluidc chip. The
fundamental resonance frequency of the transducer was about 2.4 MHz. The chip contains one inlet and one outlet. Polymer
shelled MBs with a concentration of 108 MBs/ml was diluted 1000 times and injected through inlet. The chip was placed
under the transmission light microscope. The light transmitted through a 300×300×110 µm3 sized sono-cage was captured by
CCD camera [5]. The chip was kept under stationary position for some time to avoid pressure gradient. The excitation
voltage of the transducer was varied between 1 Vp-p to 10 Vp-p and the frequencies were changed within the range of
2.3 MHz to 2.8 MHz.
3. Results
As shown in Figure (1a), there were no movements in MBs below 7 Vp-p and at 7 Vp-p the MBs started to actuate rapidly
and trapped at pressure node as shown in Figure (1b). When the driving frequency was changed from 2.3 MHz to 2.8 MHz,
the trajectories of MBs motions were varied.
4. Discussion and Conclusion
Initial observation indicates that the polymer shelled MBs behave as polystyrene micro beads of size around 5µm and cells
[2]. Therefore polymer MBs and cells could be trapped in close proximity if introduced simultaneously. This makes it
possible to study one to one interaction between cell and MB that may provide an opportunity to study cavitations associated
mechanism, for e.g., sonoporation, drug delivery mechanism and cell lysis.
References
[1] Postema, Michiel, and Odd H. Gilja. "Ultrasound-directed drug delivery."Current pharmaceutical biotechnology 8, no. 6 (2007): 355361.
[2] Wiklund, Martin, and Björn Önfelt. "Ultrasonic manipulation of single cells." InSingle-Cell Analysis, pp. 177-196. Humana Press, 2012.
[3] Wiklund, Martin, Roy Green, and Mathias Ohlin. "Acoustofluidics 14: Applications of acoustic streaming in microfluidic devices." Lab
on a Chip 12, no. 14 (2012): 2438-2451.
[4] Sirsi, Shashank R., and Mark A. Borden. "Advances in Ultrasound Mediated Gene Therapy Using Microbubble Contrast
Agents." Theranostics 2, no. 12 (2012): 1208.
[5] Wiklund, Martin, C. Günther, R. Lemor, M. Jäger, G. Fuhr, and Hans M. Hertz. "Ultrasonic standing wave manipulation technology
integrated into a dielectrophoretic chip." Lab on a Chip 6, no. 12 (2006): 1537-1544.
(a)
(b)
Figure.1 Micrographs of microfluidic chip filled with polymer shelled MBs (a) below 7 Vp-p (b) above 7 Vp-p
102
P20
Evaluation of a Portable SoC-based Bioimpedance System for Plethysmography Applications
J Ferreira1,2, F Seoane1,2 and K. Lindecrantz2
1
School of Engineering, University of Borås, Sweden, 2 School of Technology and Health, Royal Institute of Technology, Stockholm,
Sweden
E-mail: [email protected]
1.
Introduction
The application of Electrical Bioimpedance (EBI) technology for respiration function monitoring is one of the earliest noninvasive monitoring applications of EBI measurements and is commonly known as Impedance Pneumography (IP). Already
in 1969, NASA used IP to monitor the breathing of the astronauts during the Apollo XI mission. Since then, EBI technology
has improved to a great extent and it can accurately correlate with volume estimations obtained from spirometers.
Respiratory volume and flow signal extracted from IP during tidal breathing contains pathological signs of Chronic
Obstructive Pulmonary Disease (COPD), cystic fibrosis, or asthma among others. Few years ago, Analog Devices introduced
the first System-on-Chip (SoC) solution that perform complex impedance measurements, named the AD5933, that in
combination with a custom Analog-Front-End (4E-AFE) enabled the measurement of Bioimpedance using a tetrapolar
configuration [2]. The AD5933 has been used successfully in EBI applications e.g. an implantable impedance spectroscopy
[1] or Body Composition Assessment using Textile Electrodes [2]. In this work, the performance of the AD5933+4E-AFE for
continuous impedance measurements was evaluated for the implementation of impedance plethysmography applications.
2.
Materials and Methods
The AD5933-Based Bioimpedance Meter (AD5933-EBIM) used in this work, shown in Figure 1, it is a battery operated
portable tetrapolar spectrometer. It uses Bluetooth technology to transfers control messages and data between device and a
PC station. The AD5933-EBIM dimensions are 50x90x15 mm, and 70 gr of weight including the battery and a plastic box.
The maximum continuous impedance estimation frequency and system performance error were assessed over 2R1C
electrical circuits for the excitation frequencies of 50, 100, 200, 300 and 400 kHz, recording a total of 30 seconds for each
excitation frequency. Also the Transthoracic Electrical Bioimpedance (TEB) measurements were recorded in a subject that
was in sitting position and relaxed, using a tetrapolar Lateral Spot Electrode Configuration and repositionable EKG Ag/AgCl
3M Electrodes. The obtained TEB signal was processed using MATLAB to obtain the respiration and cardiac signals (∆Z)
and its first derivative signal (dZ/dt).
3.
Results
The experimental maximum impedance estimation time had an averaged value of 1.791 ms, therefore the maximum
impedance estimation frequency is approximately 550 Hz. The maximum impedance magnitude error over the 2R1C circuit
was 0.26% at 400 kHz with a maximum standard deviation of 0.04 Ω at 50 kHz. A 23 seconds recording of the TEB signal
Zraw is shown in Figure 2 upper plot, were the cardiac and respiratory components could be observed, as well as high
frequency content due to the AD5933 impedance estimation error. The filtered respiratory signal Zresp is also displayed in
Figure 2 upper plot with a dashed line. The respiration interval appears to be approximately 3.5 seconds per cycle, giving an
average respiration rate of 17 breaths per minute. In Figure 2 middle and lower plots the cardiac signal is displayed, the beatto-beat interval as extracted from the plots is approximately 0.91 seconds giving a heart rate of 66 beats per minute. Some
parameters for Impedance Cardiography analysis can be extracted from such as the increment difference for ΔZ signal with a
value of 0.17Ω, the peak value for dZ/dt which is 1.55 Ωs-1, or the baseline thoracic impedance Z0 value of 29.4 Ω.
Figure 1. Portable AD5933 EBIM
Figure 2 . TEB impedance and respiration, filtered impedance (ΔZ) and first derivative (dZ/dt) plots
4.
Conclusion
The first performance tests over a 2R1C circuit showed that the system could perform continuous impedance measurement
for a maximum frequency of 550 Hz and with a magnitude error below 0.26%. In Figure 1.b, the obtained TEB signal
exhibited a good performance before any signal processing, the cardiac and respiratory components could be observed. The
obtained results suggest that this type of system could be used in plethysmography applications such as pulmonary flow or
ICG assessment among others, also enabling the development of portable instrumentation that could be integrated into textile
garments using textile electrodes.
5.
[1]
[2]
103
References
P. Bogónez-Franco, A. Bayés-Genís, J. Rosell et al., “Performance of an implantable impedance spectroscopy
monitor using ZigBee,” Journal of Physics: Conference Series, vol. 224, no. 1, pp. 012163, 2010.
J. Ferreira, F. Seoane, and K. Lindecrantz, "AD5933-based electrical bioimpedance spectrometer. Towards textileenabled applications.", doi: 10.1109/IEMBS.2011.6090891, pp. 3282-5, 2011.
103
P21
INTEGRATION OF Bio-Patch AND iMedBox FOR IN-HOME HEALTHCARE AND SERVICES
1
1
1
1
1
Geng Yang ,Li Xie , Zhibo Pang1,2, Qiang Chen , Lirong Zheng
2
Royal Institute of Technology (KTH), Stockholm, Sweden. Corporate Research, ABB AB, Västerås, Sweden
1. Introduction
Among many other countries, Sweden is undergoing hospital restructuring by reducing the number of hospital beds and
increasing the proportion of home healthcare. By moving the routine medical check and other healthcare services from
hospital to the home environment, the limited hospital resources can be released to the people with urgent needs. Especially
in the background of global ageing and the prevalence of chronic diseases, in-home healthcare and services can drastically
lower down the total expenditure on medical care/treatment, therefore, it is promising for ICT enabled healthcare industry in
the near future. In this paper, we introduce a micro chip based Bio-Patch, and a tablet PC based intelligent medicine box
(iMedBox). By combining the Bio-Patch and iMedBox together, the concept in-home healthcare system is presented.
2. Bio-Patch and iMedBox Based In-home Healthcare System
An ultra-low power, tiny-sized application specific integrated circuit has been developed for bio-electrical sensing purpose.
The developed microchip has successfully measured ECG, EEG, EOG, and EMG signal. A temperature sensor is on-chip
integrated which can be used for body temperature measurement. Based on this microchip, we developed a patch-like sensor
with design targets of sensor miniaturization and an improvement of user comfort. By simply applying the Bio-Patch on
user’s chest, ECG signal and body temperature can be automatically detected and transmitted to the outside world via
wireless link. Powered by silicon based integrated circuits, the implemented Bio-Patch achieves a long battery life, it can
operates for several days with a coin battery. Several prototypes have been developed using different integration
technologies. Features and corresponding results can be found in [1-3].
iMedBox has been developed based on high performance and open platform-based tablet PC. Wearable medical sensors (e.g.
Bio-Patch), intelligent medicine packages, as well as the sensors/devices from the third parties can be connected to the
iMedBox via various wireless technologies. The iMedBox can serve as a common in-home healthcare platform to deliver
various services such as the health social network, telemedicine, emergency and medication management services. Detailed
device and service integration architecture and hardware and software architecture are presented in [4].
3. Discussion
An application scenario of the proposed in-home healthcare system is illustrated in Figure 1. Although the performances of
present hardware and network infrastructure are insufficient to entirely meet our expectation, the feasibility of the proposed
architecture is confirmed.
References
[1] L. Xie, G. Yang, M. Ma:ntysalo, L. Zheng, F. Jonsson, L.-R. Zheng, "Heterogeneous Integration of Bio-Sensing Systemon-Chip and Printed Electronics," IEEE Journal on Emerging and Selected Topics in Circuits and Systems (JETCAS), vol.2,
no.4, pp.672-682, Dec. 2012.
[2] G. Yang, L. Xie, M. Ma:ntysalo, J. Chen, T. Hannu, and L.-R. Zheng "Bio-Patch Design and Implementation Based on a
Low-Power System-on-Chip and Paper-based Inkjet Printing Technology" IEEE Transactions on Information Technology in
Biomedicine (T-ITB), vol.16, no.6, pp.1043-1050, Nov. 2012. .
[3] G. Yang, J. Chen, L. Xie, J. Mao, T. Hannu, and L.-R. Zheng "A Hybrid Low Power Bio-Patch for Body Surface
Potential Measurement" IEEE Journal of Biomedical and Health Informatics (J-BHI), 2013 (accepted).
[4] Zhibo Pang, Lirong Zheng, Junzhe Tian, Sharon Kao-Walter, Elena Dubrova , Qiang Chen. “Design of a Terminal
Solution for Integration of In-home Healthcare Devices and Services towards the Internet-of-Things”, Enterprise Information
Systems, April 2013 (accepted).
Microchip
Bio-Patch
Wireless Link
ECG Signal
Body Temperature
In-home
healthcare station
Intelligent
pharmaceutical package
Figure 1: Proposed Bio-Patch and iMedBox based in-home healthcare system.
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Wearable
biomedical devices
P22
DEVELOPMENT OF A CLINICALLY-RELEVANT HIGH-Tc SQUID
MAGNETOENCEPHALOGRAPHY SYSTEM
Justin F. Schneiderman1,2, Fredrik Öisjöen3, Minshu Xie3, Maxim L. Chukharkin3, Alexei Kalabukhov3, Anders Hedström4, Mikael
Elam1,2,4, and Dag Winkler3
1
MedTechWest. 2 The University of Gothenburg,Göteborg, Sweden. 3 Chalmers University of Technology, Göteborg, Sweden. 4 Sahlgrenska
University Hospital, Göteborg, Sweden.
1. Introduction
Commercially-available magnetoencephalography (MEG) systems are presently used for a variety of neuroscience studies of
brain activity because of their high spatio-temporal resolution. However, MEG has yet to reach widespread clinical use
because state-of-the-art systems suffer from low signal-to-noise ratios (SNRs) and high up-front and running costs. Both of
these issues can be relieved with the introduction of high critical-temperature (high-Tc) superconducting quantum
interference device (SQUID) technology. The elevated operating temperature of high-Tc SQUIDs compared to their
conventional low critical-temperature (low-Tc) counterparts enables relaxed cooling requirements that both lowers cost and
improves SNRs in MEG recordings. The gain in SNR is especially high for sources close to the scalp. We aim to develop a
full-head high-Tc SQUID-based MEG system that may supplement or replace the commercially available MEG systems that
presently rely on low-Tc SQUIDs.
2. Present Status
We have recorded spontaneous brain activity with our 2-channel high-Tc MEG system depicted in Figure 1 [1]. These
recordings constituted the first demonstration of a multi-channel high-Tc MEG system and served as a validation of the
technology in recordings of low-frequency brain activity of interest.
3. Discussion
Future challenges include development and validation of a 7-channel system. Open areas of interest are optimization of the
size and geometrical distribution of the high-Tc SQUIDs in a full-head system, theoretical comparison of the information
available to a high-Tc MEG system with respect to its low-Tc counterpart, benchmarking the technologies, and quantifying
the selective and/or overall advantage a complete high-Tc MEG system may have when compared to commercially available
MEG and other neuro-imaging systems.
References
[1] F. Öisjöen, J.F. Schneiderman, G.A. Figueras, M.L. Chukharkin, A. Kalabukhov, A. Hedström, M. Elam, and D. Winkler,
Appl. Phys. Lett., 100(13), 132601 (2012).
Figure 1: Our 2-channel high-Tc SQUID MEG system. A subject sits in the subject chair with his/her head fixed in the headsupport/stabilizer. Two high-Tc SQUIDs housed inside separate non-magnetic liquid nitrogen cryostats can be placed at
nearly arbitrary locations on the subject’s head via articulated armatures (also non-magnetic).
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P24
A TABLET APPLICATION FOR CLINICAL ETHICAL REFLECTION
WITHIN PALLIATIVE CARE
1
1
2
3.4
Daniel Sjöström , Maria Rampou , Lars Sandman , Leif Sandsjö
Signals and Systems, Chalmers University of Technology, Gothenburg, Sweden.
2
School of Health Sciences, University of Borås, Borås, Sweden.
3
4
School of Engineering, University of Borås, Borås, Sweden. MedTech West, Gothenburg, Sweden.
1
1. Introduction
The personnel working in palliative care are often handling delicate and sometimes unruly situations based only on their
experiences and intuition. In a recent project focusing on ethical issues experienced at the Palliative Care Unit of the
Sahlgrenska University Hospital, a care philosophy was developed ranging from an overarching philosophy, with a number
of central values and norms, to a concrete action level specifying what the philosophy could imply in a specific situation.
The philosophy originated from focus groups made up of registered and assistant nurses discussing and documenting
everyday situations from an ethical perspective, mainly concerning conflicting views on how to act in specific situations, in
terms of patient integrity and security, and often regarding relatives or friends (i.e. “significant others” to the patient), and in
relation to spontaneous meetings, feelings, culture, treatment, lack of communication and understanding. To enable a
structured use of the resulting philosophy and enable an “organizational memory” in terms of documented strategies and
knowledge about past cases or situations the gathered information should be made easy to use by organizing it in a database.
This would enable easy documentation and retrieval of both old and new situations to facilitate ethical reflection in weekly
follow-up meetings, to support the organizational memory, and to be used as a guide when introducing new personnel.
From a biomedical engineering perspective the “database” asked for is identical to a decision support system (DSS), i.e. an
interactive software system or tool that compiles information from various sources and presents the user with options
according to application specific rules in order to support decision making in a specific situation. Decision support systems
have successfully been applied in medicine for clinical decision making and have been found to improve both practitioner’s
performance and patient outcome. Thus, the aim of this study was to develop and present a prototype decision support
system for documentation and retrieval of situations of ethical concern to be used as guide and a means for ethical reflection
in the everyday care practice at the palliative care unit.
2. Method
A focus group of stakeholders and end users was set up to get input on the potential use of the intended application. Based
on the recently developed care philosophy and ethical guidelines a number of use scenarios were presented using paper
prototypes to get the focus group’s views on functionality, design and appearance. This was done in an iterative process
where the input from each iteration and evaluation session was considered for the next round of paper prototypes and in the
software implementation using the spiral lifecycle model. With respect to present and potential future demands for the
application to be easily adaptable to various tablet devices the software development was conducted in a cross-platform
environment.
3. Results
Three main use cases were identified. The first is to provide the personnel at the PCU a way of reporting situations of ethical
concern, the second is to retrieve the stored information about past situations to share experiences and enable ethical
reflection among colleagues and allow the group to add comments, the third is a browsing function for individual repetition
and/or introduction of new personnel, i.e. the “organisational memory”. Central to all three use cases is the situation where
the ethical difficulty occurs. Thus the application is centred on a way to specify the situation in terms of present persons and
their relations or roles (nurse, spouse, friend, etc) and the circumstance (food, visit, rest, etc) that, taken together, makes the
situation ethically challenging.
Thus, the key features being developed for the tablet application are:
- Straightforward specification of the situation (persons and circumstances) with a dynamically updated list showing
available guidelines and/or past cases relevant to the specified situation.
- The possibility to retrieve guidelines and past cases from the list based on the specified situation.
- The possibility to document a new case for later evaluation with colleagues if there is no applicable past case or
guideline.
- Supporting the process of later evaluation of each case and allowing new information to be added before either
including it in the guideline/past cases or remove it from the database.
These features are currently developed as an application/embedded relational database for an Android tablet device.
4. Discussion
It is believed that the presented tablet application can be a useful tool at the palliative care unit as it contributes easy access
to both guidelines and advice based on documented past cases. The tablet application’s stand out feature compared to a
paper-based version is the immediacy of its operation making it attractive to use. This may support the use of existing
guidelines, the development of everyday care practice and the organisational memory of the palliative care unit.
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P25
BICEPS BRACHII ACTIVITY PATTERN DURING REPETITIVE ELBOW FLEXIONS USING
ULTRASOUND – EFFECTS OF FATIGUE
Frida Lindberg1, Mattias Hedlund2, Fredrik Öhberg3, Lars-Åke Brodin1, Andreas Holtermann4, Christer Grönlund3
1
School of Technology and Health, Royal Institute of Technology (KTH), Huddinge, Sweden
Department of Community and Rehabilitation, Physiotherapy, Umeå University, Umeå, Sweden
3
Department of Biomedical Engineering – R&D, Radiation science, Umeå University, Umeå, Sweden
4
National Research Centre for the Working Environment, Copenhagen, Denmark
2
1. Introduction and purpose
Active fiber strains during lengthening of the muscle have been proposed to predict muscle injury and the spatial distribution
of the fiber strains may be valuable in the etiology of fiber damage [1-2]. In this study, ultrasound strain from Tissue Velocity
Imaging (TVI) was used to describe the intramuscular activity during repetitive elbow flexions. The purpose was to study the
effects of fatigue, pre and post exercise, and determine if the regional strain pattern can be used to capture the physiological
changes.
2. Method
Eight healthy subjects participated in this study and the activity patterns based on ultrasound strain was analyzed in isotonic
contractions of the biceps brachii at 5% of maximum voluntary contraction (MVC) before and after fatiguing exercise. In
order to access the intramuscular activity pattern over time motion-mode (M-mode) strain was used (see Figure 1). The
effects of fatigue were quantified by the correlation of the strain values along one image lines at different time epochs and by
analyzing the number of strain areas.
3. Results
The results show a significant effect of fatigue (Z = -2.52, p < 0.05, r = 0.63) on the number of active strain areas and the
positive correlation between the correlation values of image lines at different time epochs and the normalized force shows a
stronger linear relationship pre fatigue (r = 0.85) compared to post fatigue (r = 0.71). See Figure 2.
4. Conclusion
We suggest the results to be due to less active motor units when fatigued and that the force regulation was mainly controlled
by the slow, fatigue resistant muscle fibers and conclude that ultrasound TVI may provide the possibility analyze the
distribution of motor units and different fiber types.
References
[1] T.A. Butterfield, W. Herzog, Quantification of muscle fiber strain during in vivo repetitive stretch-shortening cycles. J
Appl Physiol 99: 593-602 (2005)
[2] R.L. Lieber, J. Friden, Muscle damage is not a function of muscle force but active muscle strain. J Appl Physiol 74: 520526 (1993)
Figure 2: Mean correlation coefficients as a function of mean normalized force.
The red lines demonstrate the linear regression and r is the corresponding
correlation coefficient.
Figure 1: Example of M-mode strain for one subject a) pre and b) post fatigue together with c) elbow joint angle. Comparing
the M-mode images pre and post fatigue, the number of strain areas has been reduced in the fatigued state. The M-mode
images show the relative strain from the first image line in the plot and the time zero indicates the start of the selected time
interval. The red colour indicates positive strain in the axial direction and thus a contraction, while the blue colour indicates a
negative strain in the axial direction.
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