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CT
the maga z ine o f C T
•
§
Veo Ultra Low Dose – p. 32
J u ne 2 0 1 1
Spectral CT: A Brave
New World of Quantitative,
Functional Imaging
CTA Changing
Patient Management
in the ED
Veo: A New Breakthrough
is Re-writing the Rules
of Low-dose CT Imaging
Page 11
Page 26
Page 32
imagination at work
Veo is 510(k) pending at FDA. Not commercially available
in the United States.
§
table o f
c o ntents
GE Healthcare News: First-time
CT Users Embrace Brivo CT325§
page 10
Case Study:
CT Perfusion 4D Imaging
in Stroke Assessment
page 48
Clinical Value:
Making Reliable Low-dose
CT a Clinical Reality
page 20
GE Healthcare News
Welcome. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
South America Embraces
the Latest GE CT Technologies. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
New Tools to Analyze Vessel Lumen, Diseased Tissue . . . . . . . 6
Quantitative Assessment of the Lung. . . . . . . . . . . . . . . . . . . . . . . 6
Unravelling the Mystery Behind Mummies. . . . . . . . . . . . . . . . . . 7
GSI Shines at Conferences, Journal Competition. . . . . . . . . . . . 8
Optima CT660‡
Reaches Milestones. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
First-time CT Users Embrace Brivo CT325. . . . . . . . . . . . . . . . . . 10
Clinical Value
Spectral CT: A Brave New World
of Quantitative, Functional Imaging. . . . . . . . . . . . . . . . . . 11 - 19
Making Reliable Low-dose CT a Clinical Reality. . . . . . . . 20 - 24
CTA Changing
Patient Management in the ED. . . . . . . . . . . . . . . . . . . . . . . 26 - 29
Kenya Hospital Extends
Quality CT Imaging to More Residents. . . . . . . . . . . . . . . . 30 - 31
Veo‡: A New Breakthrough is Re-writing
the Rules of Low-dose CT Imaging . . . . . . . . . . . . . . . . . . . 32 - 37
Reaching New Heights
in CT Cardiac Imaging. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 - 39
Eco, Patient, and Physician Friendly:
Advanced Low-dose Imaging
Without Compromise. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 - 41
Make Every Study Exceptional . . . . . . . . . . . . . . . . . . . . . . . 42 - 43
Publications Team:
GE Contributors:
Kelley Knutson & Jodi Young
CT Clarity Editors
CT Education Managers
Andrew Ackerman
CT Marketing Manager
Olivier Adda
CT Super Premium Strategic Product
Manager, Europe, Middle East & Africa
Dr. Karthik Anantharaman
CT Marketing Manager, South Asia
Christophe Argaud
CT Advanced Applications Manager,
Europe, Middle East & Africa
Paul Ayestaran
Advanced Applications Specialist,
Europe, Middle East & Africa
Chelsea Beeler
Communications Manager
Chuck Bisordi
CT Product Development Specialist
Valerie Brissart
CT Marketing Director, Europe,
Middle East & Africa
John Allenstein
Marketing Communications Manager
CT and Advantage Workstation
Mary Beth Massat
Writer/Editorial Consultant
Nilesh Shah
Chief Marketing Officer, CT
J. Eric Stahre
General Manager, Global Premium CT
Integré
Design/Production
Jennifer Coppersmith
Design/Production Consultant
2
A GE Healthcare CT publication • June 2011
Morris Buliva
Account Manager, East Africa
Roger Cepeda
Associate General Counsel, Diagnostic Imaging
Lawrence Chia
CT Modality Manager, Southeast Asia,
Australia & New Zealand
DeAnn Haas
CT Marketing Manager, Leadership
Segment, Americas
Takuya Hiramoto
Product Marketing Specialist, Japan
John Jaeckle
Regulatory Affairs Manager
Gina Larkin
CT Marketing Manager
Huayang Liu
China HDCT Product Leader
Pascal Lucien
CT Modality Manager, Africa
table o f c o ntents
Technical Innovation:
The Model-Based Paradigm:
A New Frontier in Image
Reconstruction
page 63
Beyond the Scan:
Working Together Towards
the Sub-mSv CT Exam
page 69
Case Study
High Quality, Reduced Dose Imaging
in the Comprehensive Evaluation
of Potential Kidney Donors. . . . . . . . . . . . . . . . . . . . . . . . . . . 44 - 45
Characterization
of Renal Stones Using GSI. . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 - 47
Beyond the Scan
Techniques to Lower CT Dose. . . . . . . . . . . . . . . . . . . . . . . . 66 - 68
Working Together Towards
the Sub-mSv CT Exam. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 - 71
CT Clinical Education in the US,
Europe, Middle East, and Africa. . . . . . . . . . . . . . . . . . . . . . 72 - 73
CT Perfusion 4D in Stroke Assessment. . . . . . . . . . . . . . . . 48 - 49
Low-dose CT Imaging
of CPAM for Surgical Planning. . . . . . . . . . . . . . . . . . . . . . . . 50 - 52
Technical Innovation
System Design Combines High Performance
with Patient, Earth Friendliness . . . . . . . . . . . . . . . . . . . . . . 53 - 55
One Seamless Workflow Environment. . . . . . . . . . . . . . . . 56 - 58
The Importance of Spatial Resolution
for High-quality Cardiac CT Exams. . . . . . . . . . . . . . . . . . . 59 - 62
To receive future issues of CT Clarity,
please subscribe at: www.gehealthcare.com/CTclarity
The Model-based Paradigm: A New Frontier
in Image Reconstruction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 - 65
Andrew Menden
Regulatory Affairs Leader
Thierry Modica
CT-AW Advanced Application Specialist, Africa
Daniel Morris
CT Global Marketing Manager
Enrique Garcia-Muñiz
CT Marketing Manager, Latin America
Christoph Obermeier
CT Clinical Education Business Manager,
Europe, Middle East & Africa
Tracey Ortiz
Regulatory Affairs Leader
Konstantin Osadchiy, MD, PhD
CT Advanced Applications Specialist, Russia & CIS
Helen Peng
Regulatory Affairs Leader
Karen Procknow
CT Product Development Specialist
Linda Pucek
CT Segment Marketing Manager,
Oncology, Americas
Dario Salvadori
CT Performance & Value Strategic Product
Manager, Europe, Middle East & Africa
Saad Sirohey, PhD
Global Product Manager,
CT Advanced Applications
Stephen Slavens
Regulatory Affairs Director, AW
Cristian Toader
CT Premium Strategic Product Manager,
Europe, Middle East & Africa
Wayne Zhang
Marketing Product Manager
iscovery, Optima, Brivo, ASiR, Veo, LightSpeed, BrightSpeed,
D
Gemstone, SnapShot, SmartmA, AutomA, Performix, VCAR, Volara,
VolumeShuttle, Dexus, Centricity, CardIQ, and AppsLinq are
trademarks of General Electric Company.
*
Brivo CT325 is not for sale in the United States. Not cleared
by the US FDA.
§
Optima CT660 and Veo are 510(k) pending at FDA.
Not commercially available in the United States.
‡
© 2011 General Electric Company, doing business as GE Healthcare.
All rights reserved. The copyright, trademarks, trade names and
other intellectual property rights subsisting in or used in connection
with and related to this publication are the property of GE Healthcare
unless otherwise specified. Reproduction in any form is forbidden
without prior written permission from GE Healthcare.
LIMITATION OF LIABILITY: The information in this magazine is
intended as a general presentation of the content included herein.
While every effort is made by the publishers and editorial board
to see that no inaccurate or misleading data, opinion or statements
occur, GE cannot accept responsibility for the completeness,
currency or accuracy of the information supplied or for any opinion
expressed. Nothing in this magazine should be used to diagnose
or treat any disease or condition. Readers are advised to consult
a healthcare professional with any questions. Products mentioned
in the magazine may be subject to government regulation and
may not be available in all locations. Nothing in this magazine
constitutes an offer to sell any product or service.
A GE Healthcare CT publication • June 2011
3
Welcome
Steve Gray, Vice President and General Manager,
Computed Tomography, GE Healthcare
At GE Healthcare CT, we believe that great care happens
by design. Our organization makes decisions regarding
CT product development with one purpose in mind: to help
healthcare providers deliver the best patient care. You, our
customers, have spoken and we heard your voices loud
and clear.
For over three decades, GE has made a commitment to
developing technologies that lower radiation dose. Our
long-standing vision is clear—to be a leader in patient-centric
solutions, to design systems that deliver high-performance
imaging, and to continue developing innovations that drive
even lower dose.
You told us you want to deliver high image quality for
diagnosis at ever lower doses for all of your patients who
need a CT. We heard that you want to expand the diagnostic
capabilities of CT—to let you know more about the pathology
you are viewing to aid you in making precise, confident
clinical decisions. You want a CT system with high spatial
resolution to deliver excellent image quality that drives
advanced applications and productivity.
But how low can we go? At GE Healthcare, our goal is the
1 mSv study across all pathologies, anatomies, and studies.
Lowering dose is a core commitment in our effort to deliver
great care by design. In past issues of CT Clarity, you’ve read
how dose-reduction technologies like ASiR* deliver high
image quality while lowering dose. Now, in this issue, we
present our latest dose-lowering advancement, Veo§.
In this issue of CT Clarity, you can read how GE Healthcare
is delivering solutions to address your clinical needs and
to help you provide great care to your patients.
On page 11, read how Gemstone* Spectral Imaging (GSI)
is opening up an exciting and promising new world for
CT imaging—where clinicians can obtain quantitative
information on tissue characterization, reduce artifacts from
metal instrumentation, and enhance contrast material.
In an article on spatial resolution (page 40), you can learn
how the high spatial resolution on the Discovery* CT750 HD
improves cardiac CT imaging and why it is an important
consideration as you investigate solutions that improve
cardiac care at a lower dose.
We introduced three new systems that are designed with
great care to expand the reach of CT to patients throughout
the world. These include the Optima* CT660§ system that is
ecomagination and healthymagination validated (page 42);
the BrightSpeed* Elite that demonstrates our commitment
to bring advanced applications and dose lowering technology
across our product platforms (page 44); and the Brivo* CT325,‡
a system that extends modern CT technology to healthcare
facilities so they can provide advanced medical imaging
services to their patients—patients who may otherwise
not have access to CT imaging (page 32).
Veo is our next generation dose-lowering technology.
Learn how several healthcare providers around the world
have achieved remarkable breakthroughs in high-quality,
impressively low-dose CT imaging with Veo (page 34).
We believe this new technology will play a key role in moving
us toward our goal of the 1 mSv study across all exams
and will help you achieve your diagnostic needs at before
unheard of doses without any compromise in image quality.
In fact, you’ll learn that some clinicians actually experienced
an increase in image clarity while they reduce dose when
using Veo. Clearly, the rules of CT imaging have changed.
Read on and you’ll understand why we at GE Healthcare
are so excited about the future of CT. This last decade
was a phenomenal one—widespread adoption of the
multi-detector CT was heralded as a major advancement
in medical imaging. At GE we’ll continue to pursue innovation
that drives a more confident diagnosis at the lowest dose
in the delivery of care—together with you, great care by
design can impact healthcare across the world.
Please read and enjoy. And as always, thanks for your
continued support.
Veo is 510(k) pending at FDA. Not commercially available for sale in the United States.
§
Brivo CT325 is not for sale in the United States. Not cleared by the US FDA.
‡
4
A GE Healthcare CT publication • June 2011
A nn o u ncements
ge healthcare news
South America Embraces
the Latest GE CT Technologies
Advances in CT generate excitement
in Southern Brazil
Powered by the first new CT scintillator material in two
decades, the Discovery* CT750 HD generates excellent, high
definition image quality. This capability inspired Carlos Jader
Feldman, MD, at SIDI – Medicina por Imagem (Porto Alegre,
Brazil) to select the Discovery CT750 HD and become the
second site in South America to acquire this system.
Anticipating tomorrow’s needs, Dr. Feldman saw the ability
to capture high definition images that characterize complex
lesions, such as coronary artery stenosis, as the most
impressive benefit to his patients and practice. “I believe the
Discovery CT750 HD will allow me to accurately diagnose
ischemic patients,” he says. With excellent image clarity and
spatial resolution, Dr. Feldman expects the system will allow
for faster clinical decisions by clinicians.
Located in Brazil’s fourth largest metropolitan area with nearly
four million inhabitants, SIDI and Dr. Feldman have long trusted
GE Healthcare’s technological leadership. While it was a natural
choice to look to GE for the next generation in CT imaging,
Dr. Feldman saw the potential of Gemstone* Spectral Imaging
(GSI) to help him deliver a new level of care to his patients.
“Today’s clinical path leads to anticipating etiology of diseases,
thus, it means earlier diagnostics and more accurate treatments,”
he says. With GSI, HD, and ASiR* * all available on one system,
Dr. Feldman is thrilled at the potential to deliver a higher level
of exam accuracy while enhancing patient comfort. “I will be
able to provide patients and referring physicians a confident
CT diagnosis and broader range of exams,” he adds.
Low-dose CT makes its mark in Argentina
Innovative leadership. That’s how Dr. Sergio Julio Moguillansky,
Director of Medicina XXI SA (Neuquen, Argentina) describes
GE Healthcare and its exclusive ASiR dose lowering technology.
“The concept of reducing dose whenever possible to achieve
the appropriate diagnosis is inherent to our specialty,” he says.
“Thus, we consider every technological advance that allows
us to reduce the dose a priority.”
The hospital recently installed ASiR technology on its LightSpeed*
VCT and is experiencing dramatic low-dose results. While the
actual dose level is closely related to the type of exam and the
expected results required for appropriate patient management,
Dr. Moguillansky is excited to offer less dose to his patients who
are becoming increasingly aware of CT radiation dose.
“Patients are addressing the dose issue with our clinicians,
most notably the pediatricians,” he says. “With ASiR, we
can demonstrate our commitment to providing the proper
diagnosis through the ALARA principle.”
At Medicina XXI SA, CT imaging volume averages 40 patients
each day across a wide spectrum of indications—abdominal,
thoracic, vascular, and neurological conditions. High-quality
and fast imaging capabilities are a primary objective at the
facility, says Dr. Moguillansky. By offering substantial dose
reductions at a similar image quality, ASiR fulfills the facility
requirements and helps alleviate concerns over dose.
“Our expectations are very high,” adds Dr. Moguillansky,
“and we are pleased to implement this technology due to the
increasing benefit that it will bring to our clinical practices
and particularly, to our patients.” n
“I will be able to provide
patients and referring
physicians a confident
CT diagnosis and broader
range of exams.”
**In clinical practice, the use of ASiR may reduce CT patient dose depending on the
clinical task, patient size, anatomical location and clinical practice. A consultation
with a radiologist and a physicist should be made to determine the appropriate
dose to obtain diagnostic image quality for the particular clinical task.
– Dr. Carlos Feldman
A GE Healthcare CT publication • June 2011
5
ge healthcare news
ann o u ncements
New Tools to Analyze Vessel Lumen, Diseased Tissue
CT imaging is changing the way clinicians diagnose cardiac
disease. Yet, the large volume of data generated by today’s
advanced systems can impede workflow if clinicians don’t
have the right tools to process the information. As an integral
part of Dexus*, CardIQ* Xpress Reveal, streamlines your
workflow so that exams of the heart and coronary anatomy
are ready to review the instant you’re ready to read. Two enhanced tools are designed to help clinicians improve their
diagnosis. The new PlaqID plaque analysis tool allows clinicians
to visualize both calcified and non-calcified plaque to determine
the amount of atherosclerosis. This new tool also offers
Coronary tree
Cardiac perfusion
customizable color mapping to improve visualization of plaque
pathology for a better understanding of the severity of disease.
The GE exclusive relative perfusion tools use sophisticated
segmentation techniques to color code the myocardial tissue.
Hypodense lesions are displayed to better visualize ischemic
heart disease to aid in treatment planning. Plus, the new hybrid
display view combines the coronary arteries and perfusion
map to correlate the vessels to diseased tissue.
CT is an excellent non-invasive alternative for diagnosing
coronary artery disease. Using CardIQ Xpress Reveal speeds
assessment of the patient’s cardiac disease state by delivering
more information in a simpler, faster, smarter way. n
PlaqID
Quantitative Assessment of the Lung
Now available, Thoracic VCAR* provides the physician with
a set of quantitative tools that will aid the physician in the
assessment of thoracic disease diagnosis and management.
The software provides automatic segmentation of the lungs
and airway tree, as well as tracking of the airway tree. The
software will also provide the quantification of Hounsfield units
and display by color the thresholds within a segmented region.
Key features include:
• Automated segmentation of right and left lung airways—
ease of use assists in quantification of lungs and airways;
• One touch 3D airway tracking with automated
measurements—simple user interface aids in analysis
and review;
• Lung Lobe segmentation—intuitive interactive lobe
segmentation that allow for reporting of quantitative
measurements by lobes; and
Together these capabilities provide an integrated application
for a comprehensive evaluation of a lung CT image. The analysis
tools are married to an easy-to-use reporting capability that
automatically captures
the analysis results. The
end result is a clear and
concise clinical report
that is generated during
the reading process and
specifically designed for
the communication of
vital medical information
to referring clinicians
and patients. n
Parenchyma analysis
• P
arenchyma analysis—parenchyma protocol for generating
quantitative measurements displayed as percentage/
liters of volumes of abnormal density.
Lung lobe segmentation
6
A GE Healthcare CT publication • June 2011
Volume rendering segmented lobes
with segmented trachea
A nn o u ncements
ge healthcare news
Unravelling the Mystery
Behind Mummies
Finding out the details underneath the bandages of the
mummies from the Milwaukee Public Museum is what Carter
Lupton, PhD, Curator of Ancient History, Department Head
at the museum, hopes to do thanks to the most advanced
CT technology by GE Healthcare, the Discovery* CT750 HD.
Three of the mummies from the museum collection were
scanned in April, 2011 to find out more information about
their gender, age and causes of their death.
In collaboration with GE Healthcare, researchers
from the Milwaukee Public Museum used
the latest GE CT imaging technology
to look back through time and start
unraveling details about how three
mummies—two from ancient
Egypt and one from Peru—lived
and died.
This isn’t the first time the
anthropologists have turned
to GE Healthcare for
assistance, and as GE’s
CT imaging technology has
improved, so too has their
knowledge of the mummies’
history. One of the Egyptian
mummies, named Djed-Hor,
was first scanned in 1986.
Then again in 2006, another scan using better technology
revealed a silver dollar-sized hole in his skull, leading
the anthropologists to conclude he had undergone
a primitive form of brain surgery.
To best help the museum unravel the mummy mystery,
GE Healthcare provided a cutting-edge Discovery CT750 HD
along with Gemstone* Spectral Imaging (GSI), which
offered high quality images and a dramatic level
of detail. GSI also allows researchers to distinguish
one type of tissue from another in order to better
understand the makeup of the mummies’ bodies
and other material.
Dr. Lupton and his research team used the high
resolution images from the CT scanner to learn
more about ancient medical skills and knowledge,
as well as create 3D holographic representations
of what the mummies would have looked
like when they were alive.
“We’ve been doing this for 25 years with GE.
Every time we’ve come out, it’s a different
generation of technology, better imaging,
better information, better ways, and it’s
faster too,” Dr. Lupton added. n
An ancient Egyptian mummy is scanned.
CT scan of a Peruvian mummy.
A GE Healthcare CT publication • June 2011
7
ge healthcare news
ann o u ncements
GSI Shines at Conferences, Journal Competition
American Society of Spine Radiology
At the American Society of Spine Radiology (ASSR) conference,
Dual Energy Spectral CT of the Instrumented Spine: Tuned
Monochromatic Imaging Improves Quality over Traditional
Techniques won third place in the Mentor Award Program.
The authors, James M. Kessler, MD, MPH; J. Rios, MD, PhD; M.
Ellestad; P. Pawha, MD; A. Doshi, MD; E.G. Stein, MD, PhD;
and Lawrence N. Tanenbaum, MD, FACR, demonstrated
how employing Gemstone* Spectral Imaging (GSI) in
patients post-spinal fusion produced excellent image
quality with reduced spinal canal artifact and optimal
hardware visualization.
“Historically, quality imaging of the spine in patients post
hardware fusion remained fraught with prohibitive
artifacts utilizing traditional polychromatic CT scanners,”
explains Dr. Kessler.
The authors displayed examples of CT myelography
with and without the benefits of spectral imaging and
demonstrated a markedly improved capacity for clear
visualization of the central spinal canal and its contents,
including the spinal cord and nerve roots. Dr. Kessler notes
that in many cases, spectral CT myelography differentiated
soft tissue in a similar manner to MRI allowing for
optimal depiction of the nerve roots and adjacent soft
tissue structures.
“This technique virtually eliminates the artifact,” he explains,
“and the ability to generate the same high quality exam as
we would expect in non-instrumented patients opens up
a new opportunity for patient management in those who
might otherwise have persistent chronic symptoms.”
Society of Gastrointestinal Radiology
“We found that the readers had improved sensitivity, specificity,
and diagnostic confidence when using the material density
images with color and the attenuation curves compared to
140 kVp or 70 keV images alone,” Dr. Ruhland says. “Of
clinical importance is that using the spectral CT data, the
radiologists were able to accurately determine whether
the renal lesion was enhancing or non-enhancing, thereby
avoiding unnecessary and costly additional tests.”
Dr. Ruhland acknowledges that while further study is needed,
she is hopeful that this first place paper demonstrating
the successful use of spectral CT to characterize renal
lesions will ultimately help reduce healthcare costs associated
with working up indeterminate renal lesions seen with CT.
Also at SGR, the University of Alabama at Birmingham
earned the award for First Place Poster. Desiree E. Morgan,
MD, Vice Chair for Clinical Research, accepted the award
for the poster, Dual Energy Spectral MDCT of the Pancreas:
Imaging Beyond Anatomy.
“The poster captures an exciting new area that deserves
further exploration by demonstrating the large number of
applications for spectral CT imaging,” says David N. Bolus, MD,
Assistant Professor, a co-author.
Dr. Morgan agrees that spectral CT created excitement
and “a groundswell such that I have not seen before at a
clinical symposium. The images were clearly different than
traditional CT—my fellow gastrointestinal radiologists and
genitourinary radiologists all wanted to learn more about this
intriguing new technique.”
“The ability to capture material density,” Dr. Morgan continues,
“and quantitatively differentiate things such as fat and iron
in the liver, for example, is quite remarkable.”
GSI won two different awards at this year’s Abdominal
Radiology Course meeting, a joint meeting of the Society
of Gastrointestinal Radiology (SGR) and the Society of
Uroradiology (SUR). The first place paper from the SUR
was awarded to Jessica Ruhland, MD; Amy Hara, MD;
Alvin Silva, MD; Rishi Gosalia, MD; and Qing Wu, MD,
of the Mayo Clinic Arizona for the Assessment of Renal Lesion
Enhancement: Comparison of Single and Dual Energy CT.
According to Dr. Ruhland, the study reported on the
evaluation of five image datasets by two radiologists blinded
to diagnosis: 140 kVp; 70 keV monochromatic; material
density (MD) water/iodine; MD iodine with color; and
attenuation curves from 40 to 140 keV.
8
A GE Healthcare CT publication • June 2011
Drs. Morgan and Bolus stress that what is truly important
will be the future impact on patient care—and how
radiologists, by utilizing spectral CT, can aid referring
physicians in making patient management decisions.
Adds Dr. Bolus, “When our research helps propel further
utilization of a technique, so that it is widely used
throughout the medical community, then for us it truly
becomes ‘groundbreaking’.”
A nn o u ncements
Chinese Journal of Radiology
Initiated by renowned radiology opinion leaders and senior
editors, the Chinese Journal of Radiology (CJR) held the
Spectral CT Research Paper Competition in September, 2010.
Thirty-four spectral CT research papers were submitted
covering in-vitro experiments, impact on image quality,
artifact reduction, tissue characterization, differentiated
diagnosis in oncology, hemodynamic studies, and
therapy evaluation.
ge healthcare news
After the thorough evaluation, the committee selected
eleven papers—all using GE Healthcare’s GSI—for publication
in the Spectral CT Special Edition this past spring.
Professor Hong Gao, Editor-in-Chief of CJR, says, “CT
Spectral Imaging is an exciting new study area of radiology.
From all of the 34 submitted research papers, we saw
its fundamental impact on our CT practice and research.
We look forward to more promising clinical applications
and research in the future.” n
Optima CT660 Reaches Milestones
GE Healthcare is pleased to announce the 100th Optima* CT660§
will be delivered to Olbia Hospital in Sardinia for the S.
Raffaele Foundation. Since the global introduction of the
system in April, 2010 over 200 orders worldwide have
been received.
Program, and Dr. Mohammad Alshaji, Director of the Medical
Department, and the Royal Commission Hospital team
to celebrate the installation of this new system. This new
system will deliver excellent CT imaging to the Al Jubail area
in the Eastern Province of the Kingdom of Saudi Arabia.
Of the 200-plus orders, nearly half of the sites are installed
and operational as of April, 2011. This high demand
demonstrates that the Optima CT660 is answering the
clinical imaging needs of radiologists.
Inauguration symposium at St. Rembert Hospital
An inauguration symposium took place in Torhout, Belgium
at the St. Rembert Hospital—the first European site to
receive the Optima CT660 with ASiR and Overlapped
Reconstruction options. The Overlapped Reconstruction
feature enables 128 slices per axial rotation.
The symposium included invited speakers on cardiac
CT and dose reduction technologies, a live demonstration
on post-processing applications, and a lecture comparing
CT with conventional radiology.
Royal Commission Hospital Team
Royal Commission Hospital
GE Healthcare recently installed the first Optima CT660
with ASiR in the Middle East region. The local GE team joined
Mr. Abdul-Rahman Alhewar, Director of Health Service
St. Rembert is a medium-sized hospital with a 250-bed
capacity and offers healthcare services to a population
of 50,000 in West Flanders. The CT system is being used
for all protocols, including emergency, cardiovascular,
and cardiac imaging, and current daily patient volume
is approximately 40 patients.
Geert Bibau, MD, Chief of the Radiology Department,
explained that among the reasons for choosing
Optima CT660 with ASiR were the excellent post-processing
capabilities and dose reduction technologies. n Optima CT660 is 510(k) pending at FDA. Not commercially available in the United States.
§
A GE Healthcare CT publication • June 2011
9
ge healthcare news
A N N OU N C E M E N T S
First-time CT Users Embrace Brivo CT325
Across the world, healthcare providers who are first-time CT
system buyers are discovering they don’t have to compromise
between value and performance. The Brivo* CT325§, a
GE Healthcare CT scanner developed and manufactured
in China, achieves the balance of an attainable, reliable, and
capable CT scanner.
Just as the compact system fits new users’ needs, GE’s service
and support is designed to offer the same. The latest advances
in service technology, such as remote diagnostics, help maximize
system uptime and resolve many service calls remotely.
Maintenance and service elements coupled with comprehensive,
flexible training solutions, enables each organization to meet
its service and support needs.
“This is reverse innovation at its best,” says Wayne Zhang, Product
Manager, GE Healthcare, China. “We’ve designed the Brivo CT325 “The images and the applications are excellent and reliable,”
says Zeng Xianming, MD, Director of the Radiology Department,
with advanced GE technologies and leading-edge features in an
Anhua Traditional Chinese Medicine Hospital, Hunan province.
ultra-compact, space-saving system that provides the efficiency
and resolution required for many types of routine CT procedures.” “With the speed of the system, we can image as many as 30 to 40
patients in one day without any overtime scanning. This has
Brivo CT325 was created with the new user in mind—by reducing
helped us provide better support to other departments
the number of steps needed to position and release the patient,
in the hospital.”
the table design helps streamline CT exam workflow and increase
Brivo CT325 combines simplicity with performance—
throughput. The operating console combines both image
incorporating CT perfusion, CT colonography, vessel analysis,
acquisition and post-processing with advanced applications,
and advanced volume analysis including averaging, MIP,
simplifying management of multiple tasks from a single location.
MinIP, and volume rendering.
“The Brivo CT325 imaging capabilities fulfill the various clinical
“Priced affordably for facilities that couldn’t previously afford
needs of the average user,” says Qui Jianxing, MD, PhD, Peking
to implement CT, Brivo CT325 embraces GE’s healthymagination
University First Hospital and the clinical evaluation site for
initiative and increases access to CT imaging,” Zhang adds.
the system. “The system is very reliable, enabling us to scan
patients all day.”
In fact, for 67% of the sites implementing Brivo CT325, this
is the first CT system purchased. After a successful launch in
Reliable, high-quality imaging is assured with Auto mA to
China, Brivo CT325 was introduced in Asia-Pacific, India, Latin
improve signal-to-noise ratio and optimize dose; the bowtie
America and Africa. Learn more how one facility in Kenya—
X-ray beam-shaping filters to maintain uniform X-ray at the
Jocham Hospital—is using the Brivo CT325 to better serve
detector, minimize surface dose, and reduce X-ray scatter;
its patients (page 32). n
the beam-tracking system, which contributes to higher dose
efficiency by automatically measuring the position of the
beam and adjusting the collimator using data transferred
in real time; and, the high-absorption efficiency
(98%) and stability of GE detectors for high
image quality with optimized dose.
A head exam on Brivo CT325 at Anhua
Traditional Chinese Medicine Hospital.
Brivo CT325 is not for sale in the United States.
Not cleared by the US FDA.
§
10
A GE Healthcare CT publication • June 2011
Qingdao No. 5 People’s Hospital.
G emst o ne S pectral I maging
clinical val u e
Spectral CT:
A Brave New World
of Quantitative,
Functional Imaging
CT has long been considered an excellent method for viewing high-resolution images
of human anatomy in a non-invasive manner. It has been used in conjunction with
PET and MRI—devices that can image tissue and organ function—to bring together
anatomic and morphologic information for a more precise patient diagnosis and
treatment plan.
“GSI’s spectral
HU curve and
material-basis analysis
provides us with
information on material
characterization and
quantification—this
is revolutionary.”
While CT is “an excellent technique with good spatial and temporal resolution, the
soft tissue contrast and ability to discriminate normal and pathological tissues is
sometimes inferior to other imaging techniques,” says Valentin Sinitsyn, MD, PhD,
Chief of the Radiology Department at the Federal Center of Medicine and Rehabilitation
(Moscow) and Professor and Chair of Radiology, School of Fundamental Medicine
at Moscow State University. This limitation has led to the utilization of other functional
imaging techniques in conjunction with CT imaging—which may result in additional
studies and potentially higher healthcare costs.
However, CT is closing the gap between anatomical and alternative functional imaging
thanks to advances in spectral CT and the introduction of Gemstone* Spectral Imaging
(GSI) on the Discovery* CT750 HD scanner. Today, GSI is beginning to change the way
radiologists across the world utilize CT imaging.
– Prof. Xiao-Peng Zhang
A GE Healthcare CT publication • June 2011
11
clinical val u e
G emst o ne S pectral I maging
Gemstone Spectral Imaging
Gemstone Spectral Imaging (GSI) is a
dual-energy scan mode that acquires
data of an object by rapidly switching
between low kVp and high kVp energies
in less than half a millisecond. This
generates data with different attenuation
values based on the corresponding
energy levels. The result is a near-perfect,
simultaneous dual-energy acquisition
at the full 50 cm scan field of view (SFOV)
producing projection (raw) data at two
different energy levels that has virtually no misregistration. This enables raw
data-based reconstruction of dual-energy
data with the associated benefits of
quantitative material decomposition
and beam-hardening reduction from
monochromatic energy synthesis.
Projection-based reconstruction is used
to process the data. Based on known
attenuation curves, the process
mathematically transforms low and high
kVp attenuation measurements into
effective material density (MD) basis-pair
images. This is also known as material
decomposition. GSI produces these
MD pairs which are not available with
conventional contrast-enhanced CT
imaging. The make-up or composition
of the MD pairs can be selected based
on the clinical question being investigated
and materials of interest, such as iodinewater, iodine-calcium, or water-calcium.
GSI also produces a monochromatic
image, which is synthesized from the
MD images and depicts how the object
would look if the X-ray source produced
only X-ray photons at a single energy.
Specific tools have been created in the GSI
Viewer to support the data analysis of this
rich information. Tissue characterization
can be aided with the help of Hounsfield
unit (HU) spectral curves; metal artifact
reduction is enabled by interactively
switching to the optimal monochromatic
energy level. Additionally, material
identification is made possible by
displaying the effective atomic number
histograms of objects, particularly
kidney stones.
12
A GE Healthcare CT publication • June 2011
“GSI is breaking down a barrier by bringing a new type of functional imaging to CT,”
explains Jean-Nicolas Dacher, MD, PhD, Professor of Radiology and Diagnostic Imaging
and the Chief of the Department of Diagnostic Imaging at Rouen University Hospital,
(France). He routinely uses GSI, performing approximately 20 cases each week. “Plus,
with CT we have the advantage of a quick examination that can be more comfortable
for the patient,” he adds. This is compared to traditional functional imaging studies
(MR, SPECT and PET) that can last a minimum of 20 minutes to one hour, an important
consideration for very sick and elderly patients.
After conducting more than 1,500 GSI scans and 20 pilot studies in the first three
months of using GSI, Xiao-Peng Zhang, MD, Professor and Chairman of Radiology,
Peking University Cancer Hospital and Institute (China), clearly sees its clinical value.
“We believe GSI will change the way that doctors practice and interpret CT,” he says.
“GSI’s spectral HU curve and material-basis analysis provide us with information
on material characterization and quantification—this is revolutionary.”
Revolutionary is a statement echoed by Lawrence Tanenbaum, MD, FACR, Director
of MRI, CT, and Outpatient/Advanced Development, Mt. Sinai School of Medicine (USA).
“Spectral CT offers potentially revolutionary information when compared to traditional
polychromatic CT,” he says, “including the ability to reduce certain artifacts, such
as streak and beam hardening from metal, enhance contrast resolution that will
perhaps make iodine more or less conspicuous, or improve contrast resolution
by alternating energy levels to differentiate two different tissues.”
Tissue characterization
GSI enhances tissue characterization through its ability to derive images that separate
materials such as calcium, iodine, and water.
“What really impresses me is the rich tissue characterization capability of spectral CT,” says
Dr. Tanenbaum. “To look at a dense brain lesion and know whether it is hemorrhagic,
enhancing or calcified is very helpful, particularly in difficult case scenarios.”
The 101 selectable energies and monochromatic images of GSI, explains Prof. Zhang,
enable easier and clearer detection of extremely tiny structures—for example, the
pancreatic duct and membranous structures such as the greater omentum. “This
is rarely achieved using conventional CT,” he adds.
“With the GSI-generated iodine
maps, I can clearly see the
severity of perfusion deficit.”
– Prof. Valentin Sinitsyn
G emst o ne S pectral I maging
clinical val u e
Pulmonary embolism
Prof. Valentin Sinitsyn
GSI represents what is lacking in a typical CT study, says Prof. Sinitsyn. After
the Discovery CT750 HD scanner with GSI was installed at the Federal Center
in November 2009, he immediately began investigations on pulmonary emboli.
“Traditionally, CT provided an excellent depiction of the pulmonary vessels, thrombi
and emboli,” he explains. “However, it could not give us full information on the
severity of pulmonary embolism obstruction or perfusion deficit defects. With the
GSI-generated iodine maps, I can clearly see the severity of perfusion deficit.”
Upon closer review, Prof. Sinitsyn discovered he could also detect tiny thrombus
or embolus inside the pulmonary artery, which often causes the perfusion defect.
“In patients with chronic embolism,” he adds, “it is clear that if we see multiple
perfusion defects there exists a strong indication to support surgical removal of the
thrombi.” He cites a recent study where the occurrence and severity of the perfusion
defect as determined by spectral CT is a strong predictor of patient prognosis.
Prof. Dacher also uses GSI on a daily basis to generate iodine maps for lung perfusion
studies (by centering the images on the iodine). Most exciting, he says, is the capability
to view the pulmonary artery anatomy for helping to detect clots at the same time
he obtains a lung perfusion map. He can then use the anatomical and functional
information—obtained during the same study—to assess the pulmonary emboli. “It
is very interesting to see there is no match between the extension of the pulmonary
embolus and the pulmonary perfusion abnormality,” he explains.
Valentin Sinitsyn, MD, PhD, is Chief of the Radiology
Department at the Federal Center of Medicine
and Rehabilitation (Moscow, Russia) and
Professor and Chair of Radiology, School
of Fundamental Medicine at Moscow State
University. Prof. Sinitsyn is also the elected
President of the Russian National Congress
of Radiology 2011; Vice-President of the European
Society of Cardiac Radiology; and a member
of the ECR Program Planning Committee. His
interests include cardiovascular imaging, MR,
contrast media, education, and internet and
computer applications in radiology. Prof. Sinitsyn
has authored and co-authored more than
110 articles and eight books on radiology and
internet applications, edited Russian versions
of two international textbooks on MRI and CT,
and serves on the editorial boards of the
International Journal of Cardiovascular Imaging,
the Journal of Cardiovascular Magnetic
Resonance, Diagnostic Imaging (Europe) and
Imaging Decisions.
Images courtesy of the Federal Center of Medicine and Rehabilitation (Moscow)
In one particularly interesting case at the University Hospital of Rouen, pulmonary
embolus was suspected in a patient presenting with chest pain. Prof. Dacher
performed a GSI study and discovered the pulmonary artery was encased by a tumor.
“The flow was limited and there was hypo perfusion that was completely obvious on
the GSI study because we could see the anatomy and function,” he explains. “If we
had performed only scintigraphy—historically the exam of choice for these cases—
we would have only noted the reduced perfusion of the upper lobe.” This could have
resulted in an incorrect diagnosis of pulmonary embolism and possibly led to the
patient unnecessarily receiving an anticoagulant, he explains.
About the facility
Figure 1A. A GSI iodine map depicts a wedge-shaped Figure 1B. A small embolus inside the corresponding
perfusion defect in the 9th segment of the left lung.
segmental branch of the left pulmonary artery
can be seen with GSI.
The Federal Center of Medicine and Rehabilitation
(Moscow) is well known as a modern surgical
hospital specializing in high-tech neurosurgery,
abdominal surgery, gynecology, orthopedics, and
sports injury rehabilitation. The Department of
Radiology performs all radiological examinations,
including CT, MR, and nuclear scans, around-the-clock
as needed. It is also focused on scientific research
regarding new imaging technologies and contrast
media agents. As an academic hospital, the Center
offers residency and postgraduate programs as
well as clinical faculty positions in the School of
Fundamental Medicine at Moscow State University.
The first-in-Russia Discovery CT750 HD scanner
was installed here in November 2009.
A GE Healthcare CT publication • June 2011
13
clinical val u e
G emst o ne S pectral I maging
Oncology
For Prof. Zhang, the most significant use of spectral CT is to quantitatively characterize
lesions via the spectral HU curve, which graphically displays the attenuation
characteristic of a region across all 101 spectral energies.
“Using the monochromatic images, we can visualize anatomic and internal structures
of lesions, which is important for early detection.” says Prof. Zhang. He finds the
material characterization and quantification very useful in helping him identify
different types of lesions and diseases, and gaining information on cancer
at different stages.
“GSI is not simply
a new study area,
rather it is changing
the way we think and
practice CT imaging.”
Additionally, GSI provides rich and reliable hemodynamic information of tissue
with iodine quantification. “It helps us accurately identify infiltrated areas with the
iodine-based images,” adds Prof. Zhang, “and with a reliable method to evaluate
hemodynamic status, we can evaluate therapy results more confidently.”
– Prof. Xiao-Peng Zhang
Images courtesy of Peking University Cancer Hospital and Institute
Lymphoma
14
A GE Healthcare CT publication • June 2011
Figure 2A. Affected lymph node of the neck.
Figure 2B. Affected lymph node of the porta pulmonis.
Figure 2C. Affected lymph node of the mediastina.
Figure 2D. Affected node of the spleen.
G emst o ne S pectral I maging
clinical val u e
One clinical question that a traditional CT exam cannot answer is whether
or not a lesion enhances. This is often evaluated in terms of Hounsfield units,
explains Prof. Sinitsyn. Yet the value assigned may not be precise, as the
enhancement may be partially due to beam hardening artifact or artificially
inflated via image processing.
“When I see a small enhancement, I may not be able to determine if it is true or
artificial,” he says. “By comparing water and iodine images, I get the information
to quantify the area of interest based on the accumulation of iodine and objectively
determine if the lesion is a concern that requires follow-up.”
Renal stones
Graph courtesy of Peking University Cancer Hospital and Institute
Prof. Sinitsyn also uses GSI to assess renal stones. Often, where there is one kidney
stone, there are more, so it is important to know the material composition. “GSI can
help quantify the renal stone, whether it is a calcified stone or predominantly a soft
stone containing uric acid,” he says. The latter can be treated with techniques other
than surgery, Prof. Sinitsyn adds.
Prof. Xiao-Peng Zhang
Xiao-Peng Zhang, MD, is the Professor of Radiology,
Peking University Health Science Center, and
Chairman of Radiology Department, Peking
University Cancer Hospital and Institute. Prof. Zhang
also holds the positions of Chairman of Oncology
Imaging Committee, China Anti-Cancer
Association; Managing Editor, Chinese Journal
of Medical Imaging Technology; and Editor
of the Chinese Journal of Radiology, Chinese
Journal of Clinical Oncology, and Chinese Journal
of Practical Surgery. He authored three radiology
textbooks and more than 80 research papers
globally. Prof. Zhang’s research interests include
abdominal and thoracic oncology imaging
for the early detection, accurate staging, and
therapy evaluation of cancer.
In the Radiology Department of Peking University
Cancer Hospital and Institute, a GSI team of
20 experienced radiologists and researchers,
led by Professor Xiao-Peng Zhang, has conducted
more than 1,500 routine GSI scans and 20 pilot
studies in the first three months of using GSI.
They have achieved numerous promising results,
submitted 30 research abstracts and 15 research
papers to prominent journals of radiology.
About the facility
Figure 3. Spectral HU curves show the same pattern of different affected lymph nodes in the same patient
with lymphoma, which indicate these lymph nodes are of the same nature as lymphoma.
Peking University Cancer Hospital and Institute is
one of China’s most-respected centers dedicated
exclusively to cancer patient care, research,
education, and prevention. Each year, more than
300,000 patients turn to the institute for cancer
care in the form of surgery, chemotherapy,
radiation therapy, immunotherapy, or combinations
of these and other treatments.
A GE Healthcare CT publication • June 2011
15
clinical val u e
G emst o ne S pectral I maging
Reducing artifact
With the continued increase in metal instrumentation—hip and knee prosthesis and
spinal fusion, for example—the issue of artifact degrading image quality is becoming
more pronounced, explains Dr. Tanenbaum. Reducing these artifacts is an important
benefit that GSI provides in his daily practice.
Images courtesy of Mt. Sinai Medical Center (New York)
“Between 33% and 40% of our routine spine exams involve instrumentation,” he says.
Figure 4. Note the lack of metal artifact in patient with spinal instrumentation in the 110 keV image on the right compared
to the 70 keV image on the left.
16
A GE Healthcare CT publication • June 2011
G emst o ne S pectral I maging
clinical val u e
name
Dr.
Lawrence
of author
Tanenbaum
Traditional techniques are challenged by implanted metal hardware, leading to images
with beam hardening and streak artifacts.
“Spectral CT generates virtually pristine images in these most challenging circumstances
where traditional techniques often fail,” Dr. Tanenbaum adds. “We can restore the
information in areas that were previously deteriorated by artifact and thus, substantially
improve the imaging results in these difficult cases.”
Recently at the European Congress of Radiology (ECR) 2011 annual meeting,
Prof. Dacher presented a study demonstrating that he could more easily obtain high
quality images of the femoral arteries in patients with metallic hip prosthesis by using
GSI. “We cannot accept limitations in the investigation of the femoral artery,
so this may be a strong advantage of GSI.”
Enhancing contrast resolution
Iodine-based contrast material used in CT imaging is very well suited to being
manipulated—either enhanced or eliminated, explains Dr. Tanenbaum. “Not only
can we make the iodine more useful, but it provides an opportunity to deal with
sub-optimal contrast administration,” he adds.
Radiologists can either make the contrast more conspicuous in the image by adjusting
the energy or create a material-based image that eliminates visibility of the contrast.
“With this capability, we have additional information in situations where, historically,
we’ve performed both a non-contrast and post-contrast CT study,” Dr. Tanenbaum adds.
Prof. Dacher also sees an opportunity to use GSI in cases where optimal opacification
(contrast enhancement) is not ideal, particularly in older patients or those without
good venous access. “When we acquire images with GSI, it is possible to decrease
keV and enhance the small amount of contrast media in the patient vessel.”
info
Lawrence
about N.
clinic,
Tanenbaum,
etc.
MD, FACR,
is Director of MRI, CT, and Outpatient/Advanced
Development, Mount Sinai School of Medicine
(MSSM). The school opened its doors in the fall
of 1968 and has since become one of the
world’s foremost centers for medical and
scientific training. Located in Manhattan,
MSSM works in tandem with The Mount Sinai
Hospital to facilitate the rapid transfer of
research developments to patient care and
clinical insights back to the laboratory
for further investigation.
About the facility
Mount Sinai Medical Center, named to U.S. News
& World Report’s 2009-2010 Best Hospitals
Honor Roll and ranked 19th nationally, treats
nearly 47,000 inpatients and 427,000 outpatients
each year. Renowned for its spinal cord and brain
injury rehabilitation, Mount Sinai was the first
medical school to establish a Department
of Geriatrics, as well as departments
of environmental and occupational medicine.
With more than 3,000 full-time and voluntary
physicians on staff, the hospital is a regional
leader in numerous specialties and the world’s
only center for the diagnosis and care of Jewish
genetic diseases.
“Spectral CT generates virtually pristine
images in these most challenging
circumstances where traditional
techniques often fail.”
– Dr. Lawrence Tanenbaum
A GE Healthcare CT publication • June 2011
17
clinical val u e
G emst o ne S pectral I maging
“We cannot accept limitations
in the investigation of the femoral
artery, so this may be a strong
advantage of GSI.”
Images courtesy of University Hospital of Rouen (France)
– Prof. Jean-Nicolas Dacher
Figure 5. 3D reconstructed image on left at 140 kVp demonstrates lack of imaging data due to artifact from metal
instrumentation. Note the GSI image (right) at 70 keV plus MAR ( metal artifact reduction) clearly depicts the right femoral
artery even in the presence of metal.
Figure 6. GSI helps reduce artifact and provides a diagnostic-quality study even in the presence of metal instrumentation.
The GSI image on the right at 70 keV plus MAR clearly demonstrates the reduction in artifact versus the 140 kVp image
on the left.
18
A GE Healthcare CT publication • June 2011
G emst o ne S pectral I maging
clinical val u e
Changing clinical pathways
Within one year of using GSI at the University Hospital of Rouen, Prof. Dacher and his
colleagues have changed their clinical protocols. “For pulmonary embolisms, metallic
prosthesis, and pulmonary hypertension cases, we first utilize CT with GSI,” he says.
“In lung perfusion, we have replaced scintigraphy—and in some cases MRA—with
a spectral CT exam.” The advantage of CT, he adds, is the speed of the exam and
relative patient comfort—both important considerations when evaluating very ill
or elderly patients.
“What really impresses me,” Prof. Dacher says, “is the ability to quantify the amount
of iodine within a voxel. This is a technical breakthrough that will continue to become
more important in medicine.”
At Mt. Sinai, GSI is now a routine study on patients with instrumented spines or in
neuroradiology cases when the radiologist suspects the presence of an aneurysm
clip. “Spectral CT improves the quality of some of our most challenging exams,”
Dr. Tanenbaum says, “and it certainly has an impact on the information I can provide
for surgical planning purposes.”
The additional information generated by GSI “helps with deciding the course
of treatment for the individual patient, in particular whether it should be more
conservative or aggressive,” explains Prof. Sinitsyn. He sees the potential
to eliminate additional studies with the ability to quantify areas of interest while
providing an objective and accurate diagnosis.
Prof.
Jean-Nicolas Dacher
Jean-Nicolas Dacher, MD, PhD, is a Professor
of Radiology and Diagnostic Imaging and the
Chief of the Department of Diagnostic Imaging
at Rouen University Hospital. After studying
medicine in Caen, France, he completed his
residency in Diagnostic Imaging and Radiology
at Rouen University. Prof. Dacher was a research
fellow at the Free University of Brussels, Harvard
Medical School (the Sachs Foundation Award)
(Boston), and the University of Sherbrooke (Quebec,
Canada). He has received an award from the
Société Française de Radiologie and authored
more than 130 articles and several book chapters
in French and English textbooks. Prof. Dacher’s
areas of interest include non-invasive cardiovascular imaging (MR and CT) in children and adults and
MR functional imaging of the kidneys.
“Dual-energy will further increase the significance of CT, including when and where
we use it,” he adds. It is his hope that the continued use of spectral CT will enable
the implementation of an objective, quantitative measurement of CT data—in other
words, moving away from Hounsfield units to the use of effective atomic numbers
or something similar.
Driven by an RSNA initiative, the aim of the radiology community is seeking to be more
quantitative in imaging, explains Dr. Tanenbaum. Leveraging this capability of spectral
CT should impact positively in the characterization of disease and be useful for
surveillance of patients. “It clearly gives us rich, more quantitative information than
we had before,” explains Dr. Tanenbaum. “We are only touching the surface of future
possibilities—it remains to be seen with widespread implementation and clinical
imagination where spectral CT will lead us.”
What it really comes down to is whether spectral CT will raise the level of diagnostic
confidence and reduce the reliance on multi-modality testing resulting from
inconclusive exams.
“GSI is not simply a new study area. Rather, it is changing the way we think and
practice CT imaging,” adds Prof. Zhang. “It advances CT to an entirely new level and
opens up a brave new world for the pioneer who embraces the spirit of discovery.”n
Continuing enhancements to GSI
Thanks to the collaboration of clinical leaders such as Prof. Dacher, Prof. Sinitsyn,
Dr. Tanenbaum, and Prof. Zhang, GE Healthcare continues to refine GSI. Although
Prof. Dacher has limited experience with the next iteration of GSI Viewer, he notes
that it provides faster reconstruction speed and the ability to generate MIPs
and MPRs. Both Prof. Dacher and Prof. Zhang see the potential to further reduce
patient exposure to dose, leading to greater utilization of the technique.
About the facility
The University Hospital of Rouen is located
in a city of 400,000 inhabitants made famous by
the martyrdom of Joan of Arc in 1431, its Gothic
Style Cathedral, and many paintings by Claude
Monet. This 2,500 bed hospital in Northwest
France is a full-service, multi-specialty facility that
counts among its major innovations the invention
of the transarterial aortic valve replacement (TAVI) by Alain Cribier, MD, Chief of the Department of
Cardiology and a worldwide renowned cardiologist
who implanted the first patient in Rouen in 2002.
It is through the Departments of Cardiology
and Cardiac Surgery and the Laboratory of
Cardiovascular Pharmacology (INSERM 644) that
the hospital developed a dynamic clinical and
research cardiac imaging unit utilizing MDCT, MRI,
and echocardiography.
A GE Healthcare CT publication • June 2011
19
clinical val u e
l o w d o se C T imaging
Making Reliable
Low-dose CT
a Clinical Reality
By Ramakrishnan RS, MD, DNB, Consultant Radiologist1; George Joseph, MD,
DMRD, Consultant Radiologist2; and Sundar RK, BSc, DRT, DAMIT, Clinical
Applications Manager3
ASiR* is an iterative reconstruction (IR) technique
that focuses on the modeling of the noise
properties which may enable noise reduction;
as measured by pixel noise standard deviation
in the reconstructed image and may allow
for lower dose examinations even in large
patients or studies requiring thinner slices.
Introduction
We explored new methods that offer significant dose reductions, specifically the new
reconstruction-based dose reduction technique, ASiR.**
Historically, common methods for achieving dose reduction were Automated Exposure
Control and dedicated procedure-based protocols with low techniques for pediatric
imaging, and ECG modulated mA and BMI-based for cardiac imaging. However,
these dose reduction methods are based on regulated and modulated use of mA.
Another method involves improving the image quality at lower mA values. This can be
achieved by using softer reconstruction kernels, or by using post reconstruction image
softening filters. Yet, these image space-based filter techniques do not assure any kind
of dose reduction to the patient as they are applied post scanning.
Filtered Back Projection (FBP) has been used as the reconstruction method for 30 years.
This closed form of reconstruction involves projection based data collection, filtration,
back projection, and weighting. Yet, it is based on several assumptions and does not
account for all physical parameters such as detector shape, focal spot size, image voxel
size, and photon flux variation between projections being transmitted from the patient’s
body. Thus FBP provides a calibrated, filtered image that undergoes many assumptions.
ASiR is an IR technology that focuses on the modeling of the noise properties which
may enable noise in the reconstructed image and may allow for lower dose examinations
even in large patients or studies requiring thinner slices. In routine imaging exams
at our hospital, 40% to 50% ASiR is used consistently.
MedALL Healthcare Pvt. Ltd.
Lakeshore Hospital and Research Centre
3
GE Healthcare
1
2
20
A GE Healthcare CT publication • June 2011
In clinical practice, the use of ASiR may reduce CT patient dose depending on the clinical task, patient size, anatomical location
and clinical practice. A consultation with a radiologist and a physicist should be made to determine the appropriate dose to obtain
diagnostic image quality for the particular clinical task.
**
l o w d o se C T imaging
clinical val u e
Routine imaging
ASiR may enable improvement to the Low Contrast Detectability (LCD). Following
are several patient cases demonstrating the value of using ASiR in our facility.
Case 1
An abdomen study performed with 40% ASiR maintains image quality by reducing
noise and dose (Figure 1). Note the improved visualization of contrast-enhanced
structures. In this study, the total dose delivered is 3.35 mSv (obtained by EUR-16262
EN, adult abdomen factor of 0.015 x DLP).
Dr. Ramakrishnan RS
Ramakrishnan RS, MD, DNB, is a Consultant
Radiologist at MedALL Health Care Pvt. Limited
and Malar Fortis Hospitals. He received his
degrees from Kilpauk Medical College and
Sri Ramachandra Medical College & Research
Institute. Dr. Krishnan completed a fellowship
in cardiac MRI at Sankt Gertrauden Krakenhaus
(Berlin). His areas of interest are body imaging,
cardiac CT, and MRI.
Dr. George Joseph
George Joseph, MD, DMRD, is Chief Radiology
Consultant at Lakeshore Hospital and Research
Centre, Lissie Hospital, and Lourdes Hospital at Cochin, Kerala. Dr. Joseph received his MBBS
from Government Medical College Kottayam
and medical degree in Radio-diagnosis from
Government Medical College Trivandrum. He
was one of the first radiologists trained on a CT
scanner at Sir Gangaram Hospital Delhi. Today,
his primary interests in CT imaging are abdominal
imaging and image-guided interventions.
Sundar RK
Sundar RK, BSc, DRT, DAMIT, Clinical Applications
Manager, GE Healthcare
Figure 1. Abdomen study with dose of 3.35 mSv using 40% ASiR in the bottom
image. Note the improved visualization of contrast-enhanced structures
compared to the top image.
A GE Healthcare CT publication • June 2011
21
clinical val u e
l o w d o se C T imaging
Case 2
Routine chest scan conducted with 50% ASiR at 24 mAs yielded a total dose of just 0.72 mSv
(Obtained by EUR-16262 EN adult chest factor of 0.017 x DLP).
Figure 2. 3D volume-rendered image (right) shows air way tree with transparency model of the lungs.
We have also used ASiR to scan dense objects such as metallic surgical sutures,
and implants. We have been very pleased with the visualization realized in these
challenging cases.
Case 3
Follow-up CTA of patient post-cerebral aneurysm surgery. With 50% ASiR at 76 mAs, the
effective dose was 3.1 mSv (Obtained by EUR-16262 EN adult head factor of 0.0023 x DLP).
Figure 3. 3D volume-rendered image (left) shows cerebral circulation and the positioning of the aneurysm clips. The MPVR image with MIP (center) clearly
demonstrates the vasculature even in the presence of high dense metal clips. The 3D image of the clip by itself (right) depicts the clip deployment without
any streak artifact.
22
A GE Healthcare CT publication • June 2011
l o w d o se C T imaging
clinical val u e
Coronary CTA
In our experience, the combined use of ASiR with Snapshot* Pulse—prospective gated
scans with adaptive gating—has further reduced radiation dose by 80%, for an effective
dose of 1 mSv and lower, in some cases.
Case 4
81 year-old male patient presented with angina on exertion. The study showed
atheromatus calcified plaque in all three vessels with mild to moderate luminal
narrowing. SnapShot Pulse technique was used along with 40% ASiR. The heart rate
was unstable and a dynamic padding of 25 mS was given. The DLP of the study was
77.87 mGy. cm, and the effective dose is 1.09 mSv (EDLP, ICRP chest factor 0.014).
A
About the facility
MedALL is a leading chain of diagnostic and
imaging centers across South India. MedALL
was started with a vision to provide diagnostic
services and endeavors to touch, serve and solve
health-related challenges of its customers and
to provide high level of diagnostic confidence
to referral physicians. MedALL has earned
a reputation among referral physicians and
customers for providing the highest levels
of customer satisfaction with sheer excellence
and dedication in the quality of diagnostic
services. MedALL started its journey by
acquiring some of the leading diagnostic
centers such as Precision Diagnostics in Chennai
and Clumax Diagnostics in Bangalore. MedALL
currently operates diagnostic centers in
Bangalore, Chennai, Trichy, Tirunelveli, Melur,
Pudukottai, Rajapalayam, Kurnool, Kakinada,
and Vizag.
B
About the facility
C
Figure 4. (A) 3D Volume Rendered image, (B) LAD Curved view demonstrates dense
calcification along the coronary artery wall, and (C) the blue vertical block on the ECG
shows the prospective triggering and exposure in the diastolic window.
Lakeshore Hospital and Research Center
is a multi-specialty hospital aimed at bringing
international standards in healthcare to Kerala.
Lakeshore Gastro Intestinal Surgery Unit is used
as a training center for FRCS examinations
by the Royal College of Surgeons (Edinburgh).
Lakeshore Oncology Department carried out
bone marrow transplantation and peripheral
stem cell transplantation for blood cancer
patients for the first time in the history of private
hospitals in Kerala. The hospital was the first
to introduce the artificial insulin pump for
diabetes patients in South India.
A GE Healthcare CT publication • June 2011
23
clinical val u e
l o w d o se C T imaging
Whole body scan, poly trauma application
A single CT whole body trauma evaluation is one of the most powerful tools
for managing patients with multiple critical injuries. Yet, the dose has always been
a consideration. This led to conducting whole-body scans on a limited basis and
only for specific regions to reduce radiation exposure to the patient. With the advent
of ASiR, however, we are doing our poly-trauma imaging with lower doses.
Case 5
Medium-sized male patient fell from elevated height. Initial head scan showed
intracranial hemorrhage and patient was sent to surgery. Patient was also referred
for a whole body scan to evaluate the strong suspicion of internal organ injury and
spinal fractures. Using 40% ASiR, the total whole body dose as integrated with
different regional weighting factors was 3.29 mSv (Each region’s dose was calculated
using EUR-16262 EN with adult factors of 0.0023 for head, 0.0054 for neck, 0.017
for chest, 0.015 for abdomen and 0.019 for pelvis).
Figure 5. The whole-body, contrast-enhanced scan was completed in 8 sec with 0.625 mm thin slices.
Conclusion
ASiR is an alternative reconstruction technology where the system statistics are
modeled. This may enable a reduction in pixel noise standard deviation hence
allowing for reduced mA and thereby dose.
ASiR was designed with dose reduction and LCD improvement in mind. In our
experience, the selected ASiR level correlates, to some extent, with the dose reduction
in our department. For routine imaging, we use 40% to 50% ASiR.
At MedALL Healthcare and Lakeshore Hospital and Research Centre, we have found
the benefits associated with lower radiation dose derived with ASiR are so encouraging
that we are now using the technique for all CT scans, anatomies, and routine imaging
studies. Today in our facility, the ability to image gently has become a reality with
the use of ASiR. n
24
A GE Healthcare CT publication • June 2011
GE Healthcare
Computed Tomography
Great care
by design.
No company has done more to bring low dose to
patients than GE Healthcare. That’s no coincidence —
in fact, it speaks to the single purpose that guides our
business: helping you deliver high-performance care.
Our approach is built upon a foundation of low-dose
technology. But it also encompasses the best
practices and industry exposure we’ve amassed for
decades. The result is a true end-to-end partnership
designed to help you provide lower dose patient care,
more efficiently, and more effectively.
You’re here to deliver high-performance care.
We’re here to help you do it.
www.gehealthcare.com/LowDoseCT
ASiR*
Lower image noise while
improving low contrast
detectability and image quality.
Partnership
Decades of CT experience have made
us a strong, dedicated partner who
understands healthcare’s complexities
Gemstone* Spectral Imaging
Expand information for clinical
diagnosis and workflow.
© 2011 General Electric Company
*Trademark of General Electric Company.
clinical val u e
ED IMAGING
CTA Changing
Patient Management in the ED
Convincing evidence exists to validate the
use of coronary CT angiography (CTA) to triage
patients presenting with chest pain to the
Emergency Department (ED). Yet, creating
a successful chest pain triage program requires
more than just implementing technology.
It should involve developing new protocols
and fostering collaboration between clinical
specialties to successfully change patient
management and outcomes.
1
At Baptist Hospital of Miami, Ricardo C. Cury, MD, FSCCT, Chairman and CEO
of Radiology Associates of South Florida and Director of Cardiac Imaging at
Baptist Hospital, and his colleagues have implemented ED chest pain protocols,
including the use of CTA. These protocols have helped to decrease length
of stay and the cost of care and improve clinical outcomes. The target for
the ED, he says, is to quickly assess patients with a low probability of acute
coronary syndrome.
This was no easy task. Baptist Hospital has a 100-bed ED and sees an average
of 25 patients each day presenting with chest pain. In the ED, 10 CTAs are
performed daily on a LightSpeed* VCT.
In addition to having the right technology, Dr. Cury explains, it is important
to implement and integrate the CTA protocol—developed in conjunction with
ED clinicians, hospitalists, radiology, cardiology and administration—into
the patient care process.
“Collaboration across specialties and gaining administrative support are the
major drivers for success,” he says. “We held several meetings with these groups
to define the protocols—and this is very important so everyone supports and
follows them.”
26
A GE Healthcare CT publication • June 2011
ED IMAGING
clinical val u e
“Using this protocol, we are able to significantly decrease
downstream testing after CTA because 85% of patients
could be discharged right away, including those with
negative and mild non-obstructive disease.”
– Dr. Ricardo Cury
CTA drives successful patient management
Baptist Hospital’s chest pain protocol for the use of CTA
defines five levels of care based on clinical presentation,
ECG, and cardiac enzymes (Table 1). Patient management
is determined by the degree of coronary stenosis detected
by CTA.1 Patients without stenosis are discharged to follow
up with their primary care physician. Those with mild,
non-obstructive stenosis of less than 50% are discharged
from the ED and referred for consultation with a cardiologist
or primary care physician within one week to ensure proper
treatment. In patients with moderate stenosis (50% to 70%),
a stress MPI or cardiac catheterization with fractional
flow reserve is conducted to determine hemodynamic
significance of the lesion. Patients with severe stenosis,
graded at 70% or greater are sent to the cardiac cath lab
for further diagnosis and possible intervention.
The implementation of a coordinated protocol for chest
pain patients using CTA at Baptist Hospital has led
to several remarkable results, based on the preliminary
experience of over 500 patients.
“Using this protocol, we are able to significantly decrease
downstream testing after CTA,” says Dr. Cury, “because 85%
of patients could be discharged right away, including those
with negative and mild non-obstructive disease.”
CTA Chest Pain Protocol –
Baptist Hospital
Group 1.
Patient with STEMI or new LBBB with
ischemic symptoms. For these patients,
door to balloon time is within 90 minutes.
Group 2.
Patients with non-STEMI or unstable
angina, typical anginal symptoms with
ST-segment depression, ischemic T-wave
inversion. CHF or hemodynamic instability
with chest pain. Patients are sent to the
cath lab within 24 hours.
Group 3.
Patients with a moderate to high risk
of ACS, a TIMI score greater than two,
atypical chest pain or angina lasting
less than 20 minutes, and negative
cardiac enzymes and either negative
or non-diagnostic EKG. Patients receive
a SPECT MPI.
Group 4.
Patients with a low risk of ACS, a TIMI
score of less than two, atypical chest pain
or angina lasting less than 20 minutes,
and negative cardiac enzymes and either
negative or non-diagnostic EKG. These
patients receive a coronary CTA for
detection of coronary stenosis.
Group 5.
Patients with non-cardiac chest pain.
Patients are triaged with a chest X-ray,
chest CTA (PE, Aortic Dissection or TRO),
ventilation / perfusion scan or GI work-up,
depending upon suspected pathology.
“After implementing the protocol, we experienced a 50%
reduction in length of stay that is a direct result of decreasing
patient work-up,” he continues. “When compared to our
historical data, the direct reduction in healthcare costs after
implementing the CTA protocol is $1,000 per patient.”
The number of major cardiac events (MACE) is also impressive
at 0.1% at 30 days, well below the national average found
in the literature of 2% to 4%, notes Dr. Cury.
A GE Healthcare CT publication • June 2011
27
clinical val u e
ED IMAGING
“Radiation dose reduction while maintaining
image quality§ with ASiR is a key component
in this protocol, particularly as we look
at lifetime dose for patients who received
multiple CTAs.”
Dr. Ricardo Cury
Ricardo Cury, MD, FSCCT, is the Chairman and
Chief Executive Officer of Radiology Associates of
South Florida, the tenth largest Radiology private
practice group in the United States. He is also
a non-invasive cardiovascular radiologist and
Director of Cardiac Imaging at Baptist Hospital
of Miami and Baptist Cardiac & Vascular Institute,
and a Clinical Associate Professor at Florida
International University. Dr. Cury has interpreted
more than 10,000 Coronary CT angiograms
and more than 5,000 Cardiac MRI scans.
Dr. Cury received his doctorate degree from
Santos School of Medical Sciences in Brazil and
finished his residency in Diagnostic Radiology
at MedImagem, Beneficencia Portuguesa Hospital.
He completed a Clinical/Research Fellowship
in Cardiovascular Imaging at Massachusetts
General Hospital/Harvard Medical School.
Dr. Cury won the young investigator award
sponsored by the American Heart Association,
Radiology Council, during the North America
Society of Cardiac Imaging (NASCI) in 2002.
Dr. Cury is author of more than 100 original
scientific publications in major radiology and
cardiology journals and over 200 abstracts, book
chapters, case reports, or invited presentations.
He has been the principal investigator in four
research grants. He is an associate editor of the
Journal of Cardiovascular CT and a reviewer of
several journals including Circulation and JACC.
– Dr. Ricardo Cury
The right technology
The LightSpeed VCT features GE’s ASiR* (Adaptive Statistical Iterative Reconstruction)
technology which may enable dose reduction. “We routinely use SnapShot* Pulse
(a prospective gating feature), ASiR, mA range of 250 to 500, and 100 kV to
acquire images with an average of 1 millisievert on patients under the age
of 65 with a BMI of less than 25,” he adds.
Before implementing ASiR, the average dose was 5 mSv for all patients.
“Radiation dose reduction while maintaining image quality§ with ASiR is a key
component in this protocol,” Dr. Cury says, “particularly as we look at lifetime
dose for patients who received multiple CTAs.**”
Patients with heart rates over 60 bpm are given an oral beta blocker—100 mg
PO—in the ED as soon as they are identified as a candidate for CTA, Dr. Cury
explains. “This is very important as it improves workflow and alleviates the need
for an IV beta blocker,” he says. However, if the heart rate remains high, they can
still administer the IV beta blocker in the CT room.
Using the AW Workstation, vessels are delineated via an automated
post-processing capability with additional processing completed by dedicated
technologists. Images are available approximately 15 minutes after completing
the case, and in most instances, the report is completed within one hour.
Dr. Cury understands why Baptist Hospital has been successful in implementing
CTA in the ED while other facilities have struggled to improve outcomes while
simultaneously reducing length of stay and the cost of care. “Coordination of care
between specialties, including their buy-in to follow the protocol before patient
presentation,” he says, “and having the right technology that provides good
image quality and a dose reduction strategy, are all very important contributors
to our success.” He recommends that as facilities look to the future, any investment
in CT technology must consider both the image quality and dose performance
of the system. n
As measured by noise standard deviation.
§
In clinical practice, the use of ASiR may reduce CT patient dose depending on the clinical task, patient size, anatomical location
and clinical practice. A consultation with a radiologist and a physicist should be made to determine the appropriate dose to obtain
diagnostic image quality for the particular clinical task.
**
References
Cury RC, Feuchtner G, Mascioli C, et al. Cardiac CT in the emergency department: Convincing evidence, but cautious implementation.
J Nucl Cardiol 2011;18:331–41.
1
28
A GE Healthcare CT publication • June 2011
ED IMAGING
clinical val u e
About the facility
Figure 1A. A 62-year-old male presented with chest pain to the emergency department.
His ECG and cardiac enzymes were negative. The low-dose coronary CT angiography
demonstrates a significant stenosis in the proximal LAD (>90%) with non-calcified plaque.
Baptist Health South Florida is the largest
faith-based, not-for-profit healthcare
organization in South Florida. Baptist Hospital
of Miami Emergency Department is one
of the largest in the United States. The new
67,000-square-foot ED is home to the second
busiest emergency center in South Florida,
treating more than 80,000 patients each year.
The new Center has a total of 100 exam rooms,
20 of which are part of the new Children’s
Emergency Center. Included are six
state-of-the-art trauma rooms (four trauma
rooms for adult patients, and two for pediatric
patients) equipped with sophisticated technology
to manage the most severe injuries. The new
ER is designed to maximize space, visibility
and flexibility while providing more comfortable,
spacious treatment areas for patients and
their families.
Radiology Associates of South Florida (RASF) has
served residents of Miami-Dade County since
1968. The practice is the tenth largest private
practice group in the US and provides diagnostic
radiology and interventional radiology/vascular
surgery services to patients with many types
of health conditions. RASF is affiliated with five
hospitals and 12 imaging centers.
Figure 1B. In same patient, invasive coronary angiography confirms the
presence of a high-grade stenosis in the proximal LAD (95%). Patient underwent
PCI with stent placement in the proximal LAD.
“Coordination of care between specialties, including their
buy-in to follow the protocol before patient presentation
and having the right technology that provides good image
quality and a dose reduction strategy, are all very important
contributors to our success.”
– Dr. Ricardo Cury
A GE Healthcare CT publication • June 2011
29
clinical val u e
B riv o C T 3 2 5
Kenya Hospital Extends
Quality CT Imaging to More Residents
Nestled near the Indian Ocean is the Island of Mombasa, home to Kenya’s second
largest city and its largest port. A diverse city, Mombasa traces its culture to Portuguese,
Arab, and British settlers, as well as the native Swahili people.
The Nyali Bridge connects Mombasa Island to the northern mainland. It is in this North
Coast area where residents can find quality, personalized healthcare at Jocham
Hospital that is “mwananchi” friendly—it bridges the gap between high- and
low-cost hospitals, yet offers a wide variety of services, including X-ray, ultrasound,
and CT imaging.
Sub millimeter slice of the ear
“We provide affordable medical care to people who cannot pay for the care from the
high cost institutions,” says Peter Umara, MD, Lead Radiologist of Jocham Hospital.
Yet, providing lower cost services doesn’t translate to a lack of services or quality care.
In November 2004, the hospital delivered the tiniest surviving baby in Kenya, a 1.4 lb,
5.9 inches boy born with complications at 28 weeks gestation.
Fulfilling a need
Providing access to advanced imaging equipment is half the challenge at Jocham
Hospital. Having a reliable, modern system is the other.
At Jocham, CT imaging needs center around routine studies for several reasons.
First, the cost to purchase, install, and maintain today’s most advanced multi-slice CT
scanners is prohibitive in a market such as Mombasa. Second, the aim is to provide
access to imaging services for as many residents as possible—basic healthcare is in
greater demand than specialty services. Third, the cost of technology directly impacts
the cost that Jocham charges for medical services.
3D Volume Rendering Lumbar Spine
“Brivo CT325 helps
us extend healthcare
to more people who
would otherwise not
have access to it.”
– Dr. Peter Umara
30
A GE Healthcare CT publication • June 2011
So when Dr. Umara and his colleagues wanted to replace an old CT scanner that was
often not working more than it was running, they knew the choice had to be a reliable,
lower cost scanner. However, they did not want to purchase an older, used system
that may compromise image quality and functionality.
Enter the Brivo* CT325§. Designed to extend quality care to more people, the Brivo
CT325 is a new, ultra-compact CT system with a simple interface, new table, and
gantry that help streamline CT exam workflow and increase patient throughput.
With advanced GE Healthcare technologies inside, the system has the ability
to provide excellent image quality at low dose.
“Brivo CT325 helps us extend healthcare to more people who would otherwise
not have access to it,” says Dr. Umara. “Our patients are not too well off financially,
yet the physicians need our services and diagnosis to provide better treatment.”
With the Brivo CT325, Jocham Hospital now has capability to do both.
Lowering cost. Increasing access. These are two pillars of the healthymagination
initiative from GE Healthcare. While Brivo CT325 was expected to deliver both
to facilities worldwide, it has also resulted in helping Jocham increase the breadth
of CT imaging services.
Brivo CT325 is not for sale in the United States. Not cleared by the US FDA.
§
B riv o C T 3 2 5
clinical val u e
Dr. Peter Umara
Dr. Peter Umara Marenya is the Lead
Radiologist at Jocham Hospital, Mombasa,
Kenya. His qualifications include MBchB,
MMED Radiology University of Nairobi.
Dr. Umara has completed FRCR Part 1
and is to enroll for Part 2.
Abdomen study
Brain study
About the facility
Jocham Hospital is located on the North Coast of
Mombasa Island. Since opening its doors on May
5, 1999, Jocham Hospital has served patients in
a “mwananchi” friendly way by bridging the gap
between higher cost hospitals and basic health
facilities with quality, personalized healthcare at an
affordable rate for the local residents. The hospital
offers a range of services, from outpatient care to
surgical suites to advanced imaging services such
as X-ray, ultrasound, and the Brivo CT325 system.
Chest image
“We are getting new requests for different exams, especially CT studies of the neck,”
adds Dr. Umara. He has also seen a general increase in patient volume, with many
patients returning and selecting Jocham Hospital as their preferred healthcare provider.
The Brivo CT325 delivers on two important aspects, Dr. Umara explains. “The system’s
main strengths are the image clarity in routine exams and durability,” he says.
“We often conduct 15 scans each day and the machine continues to operate well
without any issue.”
He also notes the system is user-friendly and has helped create a more efficient
workflow. Their busy days aren’t compounded by technical or operational issues
with the new CT system.
“This is the ideal system for clinics where general scanning is the primary imaging
order each day,” Dr. Umara says. “It is affordable and has a very small footprint—
for other facilities like ours, it is the type of CT scanner they should go for.” n
“The system’s main
strengths are the
image clarity
in routine exams
and durability.”
– Dr. Peter Umara
A GE Healthcare CT publication • June 2011
31
clinical val u e
Ultra - l o w D o se
Veo: A New Breakthrough is Re-writing
the Rules of Low-dose CT Imaging
Images courtesy of University Hospital, Brussels (Belgium)
0.05 mSv Follow-up Exam
for Cystic Fibrosis
Picture a world where CT dose is no longer a significant concern. Where clinicians
can use CT to obtain more information about human anatomy and conduct every
exam at 1 mSv or less. And, where clinicians and patients are confident that a
routine CT exam will provide the detailed diagnostic information at currently
unheard of doses.
Picture that world taking the first step to emerging today.
Veo*§ is the amazing advance from GE Healthcare in CT model-based image
reconstruction that has enabled clinicians to achieve a remarkable breakthrough
in ultra-low dose for CT imaging.** Several clinicians from around the world
have experienced the ultra-low dose and high image quality capabilities
of Veo and believe this reconstruction technique may enable a breakthrough
in low-dose imaging.
The Discovery* CT750 HD is the first GE system with this new game-changing
technology. The University Hospital, Brussels, was also one of the first clinical
sites worldwide to use Veo. Johan de Mey, MD, PhD, Chair of the Radiology
Department, and Nico Buls, PhD, Radiation Physicist, began testing the
reconstruction technique with a phantom to see how low they could get dose
to go and still expect to be able to view the simulated anatomy and pathology.
Figure 1. Veo images demonstrate high image
quality at ultra-low dose of 0.05 mSv (obtained
by EUR-16262 EN, using an adult chest factor
of 0.017 DLP) for 26-year-old patient with cystic
fibrosis. Acqusition parameters: 80 kV, 10 mA,
0.4 sec rotation. (Top) Veo coronal image with
lung window width and window level settings.
(Bottom) Volume rendering with segmentation
of the lobes of the lungs and bronchi.
“With a clinical chest CT at 0.05 millisieverts, we produced images where we could
see and analyze pathology,” Prof. de Mey says. “Achieving that ultra-low dose
with readable images was quite amazing.”
And while it already offers the dose-lowering technology ASiR* (Advanced Statistical
Iterative Reconstruction), Kwek Boon Han, MBBS, FRCR, FAMS, radiologist with
Asia HealthPartners (AHP) (Singapore) says, “With Veo, the image quality is
outstanding even as the dose is dramatically lowered.” He explains that Veo takes
into account the three-dimensional nature of the X-ray source, image voxel,
and the detectors in the modeling of the final image rather than assuming these
factors to be mere single-dimensional points in space.
“GE Healthcare has taken the leadership role in reducing radiation dose in CT,
culminating in the ultra-low dose CT with Veo,” Dr. Kwek adds.
Changing imaging protocols
Veo is 510(k) pending at FDA. Not available for sale in the United States.
§
In clinical practice, the use of Veo may reduce CT patient dose
depending on the clinical task, patient size, anatomical location
and clinical practice. A consultation with a radiologist and a
physicist should be made to determine the appropriate dose
to obtain diagnostic image quality for the particular clinical task.
**
32
A GE Healthcare CT publication • June 2011
Long recognized for providing greater clarity and more detail than conventional X-ray
exams, CT has changed the way clinicians diagnose disease and monitor patient
treatment. Yet, the invaluable information CT provides has contributed to increased
use and rising concerns over dose in recent years. Healthcare professionals,
following ALARA principles, are required to take every reasonable effort to
minimize exposure to ionizing radiation. Veo represents one of the most significant
breakthroughs providing the ability for a step change in dose reduction.
Ultra - l o w D o se
clinical val u e
Dr. Jean-Louis
name of author
Sablayrolles
The challenge of low-dose imaging is to perform a CT scan with the lowest possible
dose that enables a clinical diagnosis, says Dr. Kwek. It’s a balance between noise
levels that result from lower dose and image quality. So, he selected dose reductions
that commensurate with the comfort level of the reporting radiologists.
“We perform CT studies with reduced radiation dose around 0.3 mSv for paranasal
sinuses, 1 mSv for head, 0.5 mSv for thorax, 1.5 mSv for renal stone, 3 mSv for
thorax, abdomen and pelvis, and 2.0 mSv for CT colonography, including prone
and supine studies with intravenous contrast,” Dr. Kwek says.
The implications of ultra-low dose CT imaging are far reaching, particularly in
pediatric imaging. “We would like to do more CT imaging of pediatrics and young
adults, but they are more sensitive to issues of dose,” Prof. de Mey explains. While
MR is an option for these young patients, he often finds the need to administer
general anesthesia to obtain quality images in small children, primarily due
to the fact the exam takes much longer than CT. For some patients, MR may
not be suitable.
info
about clinic,
etc.
Jean-Louis
Sablayrolles,
MD, is a radiologist
at Centre Cardiologique du Nord (CCN) in
Saint-Denis, France, where he has been chief
of the CT and MRI Department since 1988.
About the facility
CCN is a private clinic created by a cardiology
group in 1973 in Saint-Denis, North of Paris,
France, that is dedicated to the treatment of
cardiovascular pathologies. With more than
180 beds, CCN performs over 1,000 cardiac
interventions each year and is considered one
of the finest cardiovascular centers in the world.
The facility has performed CT cardiac exams since
March 2000 and acquired a Discovery* CT750 HD
in July 2008.
“With Veo, we can conduct lower dose CT scans in children, too, and this
is particularly important in groups that require continued follow-up, such
as those with cystic fibrosis or lymphoma,” Prof. de Mey says.
In fact, the hospital has changed its pediatric protocols—first considering using
ultra-low dose with Veo for children receiving a CT study. According to Dr. Buls,
the revised hospital’s pediatric protocols have resulted in lower pediatric doses.
“In two months we’ll review the patient data to see if we can continue to reduce
dose in a step-by-step manner. Based on our phantom data, we believe we can
achieve a further reduction in dose.”
At Keio University Hospital (Tokyo), Masahiro Jinzaki, MD, Assistant Professor
in the Department of Diagnostic Radiology, is also impressed in the ability
of Veo to reduce dose yet improve image clarity for routine studies.
Images courtesy of University Hospital, Brussels (Belgium)
“We have drastically reduced dose without any impact on image clarity,” he says.
“Veo is completely different than any current dose lowering technique because
we can reduce dose and maintain contrast noise ratios and spatial resolution.”
Prof. Johan de Mey
Johan de Mey, MD, PhD, is Chair of the Radiology
Department at University Hospital, Brussels, and
a Professor at Brussels University where he is also
the coordinator for radiology resident training.
Prof. de Mey earned both doctorate degrees at
the Vrije Universiteit Brussel; his PhD thesis was
CT fluoroscopy in interventional radiology. As
Professor, he lectures on radiology anatomy, normal
and pathologic radiology and emergency radiology.
About the facility
Figure 2. Abdomen pelvis CT with Veo on patient with Crohn’s Disease. Compared to the FBP images
on left, note the significant noise reduction with the Veo image on the right, achieved with an ultralow dose of 1.9 mSv** at 100 kVp (obtained by EUR-16262 EN, using an adult abdomen factor of
0.015 x DLP and an adult pelvis factor of 0.019 x DLP).
Located in the heart of Europe, the University
Hospital Brussels is one of Belgium’s premier
centers of excellence in healthcare, biomedical
research and medical education. One of seven
University Hospitals in Belgium, it is closely
associated with the Brussels University. University
Hospital Brussels has gained recognition at both
a national and an international level. With its 700
beds and staff of 3,000, close to 30,000 inpatients
and 500,000 outpatients are treated every year.
A GE Healthcare CT publication • June 2011
33
clinical val u e
Dr. Kwek Boon Han
Dr. Kwek Boon Han (MBBS, FRCR, FAMS)
is a radiologist at Asia HealthPartners (AHP)
(Singapore) since the centre was established
in 2006. Prior to AHP, Dr. Kwek started
the Heart and Vascular Center for AsiaMedic
Limited in 2005. In 2003, Dr. Kwek completed
a cardiac and chest research fellowship
at Massachusetts General Hospital and Harvard
under a government scholarship (HMDP). His
primary clinical interests are in the applications
of advanced CT and MRI imaging techniques.
About the facility
Asia HealthPartners Pte Ltd is a modern medical
center in Singapore, conveniently located in the
heart of Orchard Road, which offers medical,
surgical, and diagnostic imaging services.
AHP is the training centre and luminary site
of GE Healthcare, South-East Asia. Asia
HealthPartners was awarded the “Reference
Center for Advanced Imaging, GE Healthcare”
as a commitment to deliver the latest in technology
that enhances patient care as well as to provide
advanced CT and MRI training for regional doctors.
The imaging centre has been an early adopter
of GE Healthcare CT technologies, including the
LightSpeed* VCT in June 2006, the LightSpeed
VCT XT in June 2007, the Discovery CT750 HD
in December 2010, and Veo on April 2, 2011.
Ultra - l o w D o se
Dr. Jinzaki also sees greater potential for implementing ultra-low dose studies,
such as those used for lung studies, CT colonography, and CT urography. “With
lower dose, we may be willing to replace more conventional X-ray studies to
gain the greater information provided from CT.”
Jean-Louis Sablayrolles, MD, Chief of the CT and MRI Department at the Centre
Cardiologique du Nord (CCN) (Saint-Denis, France), has been able to achieve his
goal for common chest CT exams below 1 mSv. With the additional information
gleaned from CT, the clinical value is compelling to Dr. Sablayrolles and he sees
potential to replace current imaging methods with ultra-low dose chest CT using Veo
in his practice.
“The impact of lowering dose, particularly for oncology and cardiovascular patients,
is immeasurable,” he says. “If we are conducting follow-up exams every three
or six months, it is very important to reduce the dose as much as possible.”
Greater image clarity
While lowering dose is a primary advantage of Veo, Dr. Sablayrolles also sees
what he believes are significant image quality improvements.
“In oncology studies with Veo, we can also increase the conspicuity of the tumor
for tissue characterization,” he explains. “In vascular studies, it is possible
to differentiate stenosis from occlusion and reduce the blooming effect that
results from the presence of a stent or calcified plaque.
“There are instances where a higher quality study is most important, and Veo
enables us to increase spatial and contrast resolution to visualize very small
lesions,” Dr. Sablayrolles adds.
At AHP, Dr. Kwek attributes greater image quality to the fundamental design of the
Veo algorithm. “With Veo, there is improvement in the spatial resolution of tiny
structures, such as the distal small airways in the patient,” (Figure 6).
Images courtesy of CCN (Saint-Denis, France)
Similarly, he attributes the ability to resolve small foci of calcification, particularly
in patients with nephrocalcinosis, to Veo being able to accurately discriminate
and separate the density of the image voxel.
A
B
C
D
Figure 3. Vascular run-off study using Veo illustrates the image quality and lumen visualization improvement of popliteal stent
compared to FBP technique. (A) FBP vessel tracking; (B) Veo vessel tracking; (C) FBP MIP vessel tracking; (D) Veo MIP vessel tracking.
34
A GE Healthcare CT publication • June 2011
clinical val u e
Images courtesy of Asia HealthPartners (Singapore)
Images courtesy of Asia HealthPartners (Singapore)
Ultra - l o w D o se
Dr.
name
Nico
of Buls
author
Nico
info about
Buls, PhD,
clinic,isetc.
a medical physicist
in medical sciences at University Hospital,
Brussels. His research in medical imaging
spans translational projects in medical
imaging physics, radiation dosimetry,
engineering, and diagnostic radiology.
Dr. Buls has presented internationally
and has authored one book chapter
in an international textbook and more
than 25 peer-reviewed articles.
A
Figure 5. A 38-year-old male known to have
nephrocalcinosis, presenting with microscopic
haematuria. The foci of faint calcification in the
renal pyramids are apparent in the Veo image.
The CT KUB (Kidney Ureter Bladder) scan was
performed with DLP of 118.79 mGy cm.
Benefits outweigh reconstruction time
As Veo uses a powerful new class of new reconstruction algorithms that more
accurately model noise statistics, system optics, and radiation physics in the data
acquisition process, it requires additional time to reconstruct images.
Even with extended reconstruction time, Prof. de Mey has been able to incorporate
Veo into his facility without impacting workflow in the radiology department.
As the scan is performed, the technologist has immediate access to images
reconstructed with ASiR, and, there is no change in radiologist efficiency as
the Veo reconstruction is completed in the background. Prof. de Mey uses the
analogy of a blood test—it may take an hour for results, yet it doesn’t stop the
provision of care or the flow of patients in the department. In his experience,
the patient and diagnostic benefits from the ultra-low dose Veo exams justify
the increase in reconstruction times.
Advances in computing power will continue to speed up the Veo reconstruction
experienced by today’s pioneering users. “Veo has the potential to open new
fields in CT imaging. We are only at the beginning of this new application and
anticipate rapid advancement as typically seen in CT development,” adds
Dr. Sablayrolles.
Images courtesy of Asia HealthPartners (Singapore)
Figure 4. A 58-year-old female with left
mastectomy for breast cancer currently
undergoing chemotherapy. The CT scan
was performed with DLP of 156.48 mGy cm.
A
B
Figure 6. A 72-year-old male with inoperable lung
cancer, currently undergoing chemotherapy. The
distal small airway is better appreciated with the
Veo (A) compared to the ASiR 50% image (B). The
CT thorax and abdomen was performed with DLP
of 108.25 mGy cm.
A GE Healthcare CT publication • June 2011
35
clinical val u e
Ultra - l o w D o se
Beyond comparison
Dr. Masahiro Jinzaki
“Veo may enable a greater impact on dose than many other techniques,” Dr. Buls
explains. “For example, adaptive collimation in spiral CT reduces dose by just a few
percentage points. With Veo, we are seeing dose reduction of an entirely new
order.” By developing dose reduction techniques via new reconstruction algorithms,
GE Healthcare has opened up new possibilities for much greater dose savings.
Veo will impact how and when radiologists decide to utilize CT imaging. “A key
concern with CT is the radiation dose; however, Veo may reduce that concern,” says
Dr. Jinzaki. “There will be changes in the preference of CT imaging versus other
exams, such as general radiography and MRI,” he explains.
Dr. Sablayrolles has no doubt that Veo will make a major difference in CT imaging.
After three months experience with Veo, he has repeatedly demonstrated dose
reduction and excellent image quality in study after study.
“We are at the beginning of a very interesting advancement in CT imaging,” says
Dr. Sablayrolles, “and the future of Veo lies in every application. In my opinion,
Veo is one of the major advancements in CT imaging—it is as important as the
development of helical and multi-detector CT.” n
Images courtesy of CCN (Saint-Denis, France)
Masahiro Jinzaki, MD, PhD, is an Assistant
Professor in the Department of Diagnostic
Radiology at Keio University School of Medicine
(Tokyo). He received both his medical degree,
with honors, and post-doctoral degree from Keio
University. Dr. Jinzaki has completed a research
fellowship in the Department of Surgical
Pathology at Keio University and in the
Department of Radiology at Brigham and
Women’s Hospital (Boston). He specializes
in abdominal diagnostic imaging. Dr. Jinzaki
also takes special interests and leads research
in cardio-vascular and urology imaging. His
experience with GE CT includes LightSpeed
Plus, LightSpeed Ultra, LightSpeed Ultra16,
and LightSpeed VCT. Dr. Jinzaki has been using
Discovery CT750 HD since December 2008,
and Veo since March 2011.
The true power of Veo will be found in the ability to allow a lower dose examination
while still delivering outstanding image clarity.
About the facility
Keio University Hospital was established
by Yukichi Fukuzawa in 1858 and celebrated
its 150th anniversary in 2008. In 1917, the
medical school was launched as a medical
preparatory course with Dr. Shibazaburo
Kitazato, who became the University’s first
dean, and three years later the University
Hospital was opened. Today, the hospital
has 27 diagnosis and treatment departments
and 13 central treatment departments with
over 800 clinical doctors (including resident
physicians). An average of 4,000 patients walk
through the hospital’s doors each day with
approximately one-fourth hospitalized.
On average, the Emergency Department treats
over 20,000 patients and performs 13,000
operations each year.
36
A GE Healthcare CT publication • June 2011
Figure 7. Veo ultra-low dose chest CT conducted
at 0.48 mSv (obtained by EUR-16262 EN, using
an adult chest factor of 0.017 DLP) at 100 kVp.
Veo coronal (top left); Veo fusion of volume
renderings with lobes segmentation (top right);
Veo sagittal (bottom left).
clinical val u e
Images courtesy of Keio University Hospital (Tokyo)
Ultra - l o w D o se
Figure 8. Coronal image of the abdomen and pelvis comparing FBP (left) to Veo (right). Veo image demonstrates higher image quality and less noise
compared to the FBP image at 0.97 mSv (obtained by ICRP Publication 102, using a one-year-old abdomen and pelvis factor of 0.03 x DLP).
Figure 9. Coronal image of the abdomen and pelvis with low density lesions in the liver comparing FBP (left) to Veo (right). Lesions are better demonstrated
in the Veo image at 1.88 mSv (obtained by EUR-16262 EN, using an abdomen factor of 0.015 x DLP and a pelvis factor of 0.019 x DLP).
A GE Healthcare CT publication • June 2011
37
clinical val u e
S patial R es o l u ti o n
Reaching New Heights in CT
Cardiac Imaging
The impact of spatial resolution at the University
of Washington Medical Center
Over the last decade, clinicians have witnessed remarkable
advancements in CT imaging. This includes the emergence
of hybrid imaging, which brought CT together with functional
imaging systems such as PET and SPECT, multi-slice CT, and
techniques that significantly lower radiation dose.
GE Healthcare has been a leader introducing innovations
that have redefined the clinical value of CT imaging. Now,
the company is charging ahead with another evolution
in CT technology that promises to help clinicians confidently
view even hard-to-see lesions—high definition imaging
that enhances spatial resolution.
CT has long been recognized as an imaging leader in spatial
resolution, which is the ability to distinguish two separate
structures that are a small distance from each other.
Yet, many improvements in spatial resolution over the years
were incremental—that is, until the introduction of the
Discovery* CT750 HD system.
“The Discovery CT750 HD provides better spatial resolution
and image quality than other systems in our facility,” says
William P. Shuman, MD, Director of Radiology at the University
of Washington Medical Center (UWMC).
Dr. Shuman’s colleague, Kelley R. Branch, MD, Assistant
Professor in Cardiology at UWMC, agrees that “the
Discovery CT750 HD in high definition mode offers high
detail spatial resolution needed for cardiac imaging.”
Value in cardiac imaging
Increased spatial resolution was always desired for cardiac
imaging, Dr. Branch says, especially when imaging smaller
patients and arteries.
This same detailed resolution also benefits characterization
of plaque. “Better spatial resolution helps us improve the
delineation of plaque characteristics,” adds Dr. Branch.
“We can see the lumen and the outside wall of the coronary
artery, and assess if the plaque is a concern that requires
follow up.”
Dr. Shuman believes high spatial resolution in CT will play
an important role in aiding them to detect disease within
smaller vessels. Historically, he says, this has been a
weakness of CT—the inability to successfully image the
38
A GE Healthcare CT publication • June 2011
VR heart
smaller branch vessels. This led to patients undergoing
further evaluations, such as a diagnostic cardiac catheterization,
after a diagnostic CT study.
“There is a good proportion of cardiac disease located more
distally after the first and second branches that may still
cause symptoms,” Dr. Shuman explains. “It is critical to be
able to assess the peripheral branches for coronary artery
disease, as well as capturing the extent of disease in the
proximal coronary artery.”
CT perfusion studies are another potential area for greater
clinical utility resulting from higher spatial resolution. “With
CT perfusion, it comes back to precision,” Dr. Branch explains,
“and the confidence that what you are seeing is really there.”
When evaluating the myocardium with higher spatial
resolution, for example, he is able to conduct more advanced
calculations based on the imaging study—calculations that
can help assess myocardial blood flow.
Impact on patient care
In describing the benefit of enhanced spatial resolution,
Dr. Branch points to the high negative predictive value
of CT. “As the spatial resolution increases, our confidence in
the study improves significantly and we are more confident
that we don’t have to conduct further tests to rule out the
presence of disease.”
This capability is very important not only for triaging chest
pain patients in the ED, but also reducing the overall cost
of a patient’s episode of care. Having the ability to provide
patients a rapid answer is beneficial; not just for their care,
but also to determine which chest pain patients can be
discharged from the ED.
“This consumes less resources and leads to lower costs
and we are able to see atherosclerosis that we haven’t
seen before,” says Dr. Branch.
While coronary artery disease may not be an immediate
issue for these patients, it can develop in the future and
Dr. Branch sees it as an opportunity to engage the patient
to change their behavior. “It is our hope that patients will benefit
by adopting a move toward a healthier lifestyle,” he says.
S patial R es o l u ti o n
clinical val u e
The double whammy
Vessel tree
Dr. William P. Shuman
Both Drs. Branch and Shuman credit another
GE innovation on the Discovery CT750 HD
with helping improve spatial resolution—ASiR*
(Adaptive Statistical Iterative Reconstruction).
“Using techniques such as ASiR, we have seen improvements in low contrast
detectability (LCD),** but adding HD on top of that helps us use CT to examine
the branch vessels and in some cases, provide us the images we need for a
definitive evaluation of coronary artery disease after an inconclusive SPECT
exam,” Dr. Shuman says.
Dr. Branch describes the benefit of ASiR with HD as getting a noticeable
improvement in spatial resolution without an increase in dose, almost like
“getting more information for free.” HD provides an increase in spatial resolution
and ASiR may enable LCD improvement without the need to increase dose.**
That, he says, continues to advance clinical precision. “Now CT is presumed a
lower dose study, particularly important for younger patients.” Dr. Branch also
appreciates the lower noise and virtually artifact free images when using ASiR.
William P. Shuman, MD, is Director of Radiology
at UWMC and Vice Chairman and Professor
for the Department of Radiology. Dr. Shuman
received his medical degree from State University
of New York Syracuse, and completed a residency
in radiology at the University of Vermont.
Dr. Shuman is one of the leaders in creating
cardiac CT at UW. Outside of UW, Dr. Shuman
has served as Associate Editor for the two
leading academic peer reviewed journals in
Radiology, is currently on the Appropriateness
Committee of the American College of Radiology,
and is the President of the Society of Body CT/MR.
“If we are struggling with spatial resolution in patients whose exams are likely
to have a high level of noise, such as obese patients, we can use ASiR and
HD to obtain a diagnostic study,” says Dr. Branch.
He also finds that the fine spatial resolution obtained from the use of HD
helps address the issue of artifact from blooming of calcium. Notes Dr. Shuman,
“We used to exclude patients with calcium; now we don’t.”
“These improvements—ASiR and HD—are impressive by themselves, but when
used in combination we see a substantial difference across a very broad range of
studies in spatial resolution and LCD,” Dr. Shuman continues. When faced with new
developments such as HD, he advises his peers to not become consumed with
the lack of peer-reviewed literature or research. “Until users begin to integrate a
technology into their standard-of-care, it will take time for new innovations such
as HD. You just have to be willing to
dive in and try it yourself.” And he bets
that the user will encounter a series
of pleasant surprises and find it unlike
any other technique.
Looking to the future, Dr. Branch
believes higher spatial resolution
will be a step toward redefining
the role of CT imaging. “With these
advancements, one can foresee a
future where cardiac CT could be the
first line of assessing (cardiovascular)
symptoms and assessing high risk
patients, and potentially changing
therapy based on cardiac anatomy.” n
Dr. Kelley R. Branch
Kelley R. Branch, MD, is Assistant Professor
in Cardiology at the University of Washington
Medical Center. Dr. Branch received his medical
degree from Jefferson Medical College, and
completed a residency in internal medicine
at the University of Michigan Medical Center.
In 2003, Dr. Branch received the American
College of Cardiology Merck Fellowship Award,
and, in 2007-2008, the Cardiology Teaching
Excellence Award and the School of Medicine
CME Teaching Award from UWMC. He is also
a founding member of the SCCT (Society of
Cardiovascular Computed Tomography) and
is actively engaged in several clinical studies.
In clinical practice, the use of ASiR may reduce CT patient
dose depending on the clinical task, patient size, anatomical
location and clinical practice. A consultation with a radiologist
and a physicist should be made to determine the appropriate
dose to obtain diagnostic image quality for the particular
clinical task.
**
High resolution with ASiR
A GE Healthcare CT publication • June 2011
39
clinical val u e
Optima C T 6 6 0
Eco, Patient, and Physician Friendly:
Advanced Low-dose Imaging
Without Compromise
Bigger is not always better. In the world of CT
imaging, it is efficiency and quality that matter.
That’s why clinicians across Europe and the
Middle East are embracing the Optima* CT660§—
a new CT system that is eco-friendly and
delivers high-quality imaging.
At his private practice in Burbach, Germany, Hans-Martin Klein, MD, relies on
the latest CT, MRI, and ultrasound systems to deliver high-quality imaging across
all exam types. Located near the geographic center of Europe and a major
transportation hub, Prof. Klein’s patient base extends well beyond German borders.
“Our focus is on quality medical imaging that covers all pathologies,” he says.
“We do not compromise on diagnostic power and select systems that are near
the top of the clinical application trends.” In concert with his focus, Prof. Klein
wanted a CT system that would deliver the high-quality images his referring
clinicians and patients have come to expect.
“Our focus
is on quality
medical imaging
that covers
all pathologies.”
Prof. Klein is a strong promoter that advanced imaging must also balance
with patient dose considerations. In his review of CT systems for his practice,
he searched for the right solution that would allow for meaningful and significant
dose reduction in accordance with ALARA principles.
“The Optima CT660 is the right balance for us,” he adds, with the right development
focus. It includes advanced technology such as ASiR*, a dose reduction technique.**
Today, Prof. Klein’s private practice performs an average of 45 imaging studies
each day. He can also reconstruct 3D batch files, which helps streamline his
workflow. The system has lived up to its full potential to consistently and reliably
handle the daily exam volume in his busy practice.
For Prof. Klein, the most important aspect of the Optima CT660 is quality.
– Prof. Hans-Martin Klein
Optima CT660 is 510(k) pending at FDA. Not commercially available in the United States.
§
In clinical practice, the use of ASiR may reduce CT patient dose depending on the clinical task, patient
size, anatomical location and clinical practice. A consultation with a radiologist and a physicist should be
made to determine the appropriate dose to obtain diagnostic image quality for the particular clinical task.
**
40
A GE Healthcare CT publication • June 2011
Optima C T 6 6 0
clinical val u e
Prof. Hans-Martin
Klein
“Our goal is the highest diagnostic imaging quality standard across all modalities,”
he says. Thanks to the implementation of the system, he can now offer CT
cardiac imaging studies to referring physicians and patients.
“The Optima CT660 offers a large set of applications and excellent software
for coronary evaluation,” Prof. Klein adds. “Both in cardiac prospective gated
mode and in retrospective gating we obtain excellent images at low dose.”
It is the image quality at a low dose that impresses him most. “When one of our
team members was told the dose on a neck-abdomen-pelvis exam, he thought
the value only referred to one of the three sequences, not the total exam,” says
Prof. Klein. They verified the dose was for the entire exam and the image quality
was great, he adds.
Hans-Martin Klein, MD, is a radiologist in private
practice in Burbach, Germany. He completed
his medical training at Aachen University Medical
Center, where he later held positions in radiology,
neuroradiology, and neurosurgery. Before
starting his second private practice in 2011,
he was Medical Director of Evangelist Jung
Stilling Hospital an imaging center in Siegen,
Germany, for six years. Prof. Klein owns or
co-owns nine German patents for medical and
radiation protection products, authored seven
books and over 100 articles, and presented
37 abstracts at medical meetings.
About the facility
Prof. Klein’s private practice, Medical Center
Siegerlandflughafen, provides multi-modality
diagnostics of nearly all pathologies with advanced
CT, MRI, and ultrasound systems. The center’s
primary focus is to deliver quality medical imaging
and it has a daily volume of 40 to 45 patients.
Situated near the geographical center of Europe
and a major communication hub, Prof. Klein’s
patients extend well beyond Germany’s borders.
Providing greater access to low-dose CT studies is a benefit for the radiologist
and the patient. Prof. Klein is excited he can now offer additional low-dose
capabilities to all patients, including pediatrics.
The system is both ecomagination and healthymagination validated, helping
to save energy costs—up to 60% with the energy saving mode. The Optima CT660
also has a smaller footprint than comparable systems, helping reduce or even
eliminate the cost to expand an existing room or add an addition to the facility.
The Optima CT660 is creating new high-quality imaging opportunities, such
as advanced CT cardiac imaging, for many clinicians such as Prof. Klein. Packed
with features and applications, it offers low-dose imaging while still delivering
the diagnostic image quality he demands. What’s more, thanks to its compact
design, it provides greater flexibility for installation and is kind to the earth by
consuming less energy. Reliable and eco-friendly, yet powerful—the Optima CT660
is helping redefine the next generation of affordable CT systems. n
“The Optima CT660
offers a large set
of applications and
excellent software for
coronary evaluation.”
– Prof. Hans-Martin Klein
A GE Healthcare CT publication • June 2011
41
clinical val u e
B right S peed E lite
Make Every Study Exceptional
Delivering high image quality with lower dose
Toulouse, France, is renowned as a city on the cutting edge of European technology.
As such, it is appropriate that Joseph Ducuing Hospital, located near the center
of the city, is one of the first hospitals to install the BrightSpeed* Elite with ASiR*—
a compact CT with advanced technology inside.
The hospital’s mission is to contribute to improving the health of the residents
throughout the community. This is accomplished with a primary focus on quality
across all care areas—the emergency room, surgery, maternity, endocrinology,
a center dedicated to “rare illness,” and a center for tuberculosis assessments.
It is this focus on quality and patient outcomes that led Joseph Ducuing Hospital
to select the BrightSpeed Elite CT system with ASiR. The hospital took great care
in the decision to acquire this particular system, explains Cristian Livideanu, MD,
a radiologist at the hospital. “Both referring physicians and patients are aware
of the importance of dose in CT imaging,” he says. “The BrightSpeed Elite provides
ASiR dose reduction technology and matches our requirement to fulfill the needs
of the community.”
The hospital’s initiative to reduce dose used a variety of methods, including
the low dose features on the BrightSpeed Elite system, such as ASiR, and newly
optimized protocols. During the first three months of scanning, nearly
900 patients have benefitted by lower dose .** The hospital has seen a decrease
on average of 35% for brain exams, 50% for thorax exams, 40% for abdominal
exams, and 70% for extremity studies—all while maintaining the image quality
they needed for diagnosis.
Dr. Livideanu says that the local medical community has embraced the new ASiR
technology and they have been referring CT patients to the BrightSpeed Elite
CT system. “Since installing the BrightSpeed Elite, we’ve seen a significant
percentage increase in patient referrals,” Dr. Livideanu says.
Figure 1. Excellent spatial resolution obtained
at high acquisition speed allows depiction of the
aneurysm on left renal artery (35 cm coverage
in 5 sec/1.75 Pitch/5.5 mSv [obtained by EUR16262 EN, using a adult chest factor of 0.015]).
BrightSpeed Elite is a 16-slice CT with advanced technology inside—providing
a remarkable balance between system design and speed of acquisition,
reconstruction, and post-processing capabilities to deliver the clinical information
in a short time. Thanks to this technology, Dr. Livideanu can perform high-quality
CT studies at a reduced dose and maximize patient throughput.
He considers the system a workhorse CT that can be used for virtually any exam—
from routine studies to emergency cases. Dr. Livideanu is most impressed with
ASiR for reducing dose and attributes exam volume growth to this feature.
In clinical practice, the use of ASiR may reduce CT patient dose depending on the clinical task, patient size, anatomical location
and clinical practice. A consultation with a radiologist and a physicist should be made to determine the appropriate dose to obtain
diagnostic image quality for the particular clinical task.
**
42
A GE Healthcare CT publication • June 2011
B right S peed E lite
clinical val u e
name
Dr.
Cristian
of author
Livideanu
Figure 2. Multi-phase abdominal acquisition (120 kVp, 70 to 150 mAs).
The new CT is also faster than the hospital’s previous 16-slice CT. “With a more
robust acquisition, we can better manage the more difficult cases, such as apnea
and pulmonary embolism,” Dr. Livideanu adds. “The new post-processing tools—
Lung VCAR*, Thoracic VCAR, Autobone, and VesselIQ Xpress—help the radiologists
streamline reading for faster report turn-around-times and provide accurate and
clear assessment to the referring physicians, who also express their appreciation
for the exceptional image quality.”
Even with the additional software tools and features, the BrightSpeed Elite with
ASiR was intuitive for the technologist to learn how to operate and the radiologist
to best utilize the workstation. Within one week, the staff learned how to adapt
the new technology for use in all applicable clinical cases.
Cristian
info
about
Livideanu,
clinic, etc.
MD, is a radiologist at Joseph
Ducuing Hospital in Toulouse, France, since 2008.
In 2002, Dr Livideanu received his radiology
degree in Romania where he also received
the “Cum Laude” award at the Millénium
Radiology Congress. His areas of interest include
interventional radiology, vascular, ER radiology,
and osteoarticular radiology.
About the facility
Joseph Ducuing Hospital, near the city center
of Toulouse, France, is a nonprofit, public hospital
that opened November 3, 1976. It actively
participates in the social work of protecting
and safeguarding the health of the population.
The hospital’s quality objectives and ethics
are based on principles and values that aim
to provide the best possible healthcare. Services
include radiology, emergency room, infant care,
surgery, and tuberculosis assessments.
Improving CT dose management can help maintain CT as a useful diagnostic
imaging tool for radiologists, referring physicians, and patients, Dr. Livideanu says.
He is pleased with the decision to be one of the first to select a new BrightSpeed
system in France.
“I would recommend the BrightSpeed Elite system with ASiR because of the
system’s ability to enable dose reduction,” he explains. “This system should
be present in all regions of France and elsewhere.”
Dr. Livideanu adds, “It is very amazing to see that we have conducted many CT
exams with half the dose that we used on the same patient two years ago—and
all without loss in diagnostic image quality.” n
“The BrightSpeed Elite
provides ASiR dose
reduction technology
and matches our
requirement to
fulfill the needs
of the community.”
– Dr. Cristian Livideanu
Figure 3. A low dose, 5 second acquisition on the sinus (120 kVp, 10 mAs, Pitch 1.375).
A GE Healthcare CT publication • June 2011
43
case st u dy
ABDOMINAL IMAGING
High Quality, Reduced Dose Imaging
in the Comprehensive Evaluation
of Potential Kidney Donors
Joel F. Platt, MD, Professor of Radiology and Director of Abdomen Division,
University of Michigan Hospital
Abstract
Acquisition protocols
Scanner
Discovery CT750 HD
Scan type/slice
thickness
Helical /0.625
Coverage
20 cm
Rotation time
8 sec
Total X-ray
exposure time
2.6 sec for CTA series
mA
Auto mA 260-380;
NI 27.5
kVp
100
Recon kernel
Standard
SFOV
50
DFOV
28
ASiR
30%
Contrast protocols
Type of contrast 370 mg/ml
iodinated contrast
44
Contrast
injection rate
4 ml/sec
Total contrast
amount
100 ml
Saline
injection rate
4 ml/sec
Total saline
amount
50 ml
A GE Healthcare CT publication • June 2011
MDCT has become our established method for comprehensive evaluation of subjects
who are being considered as kidney donors. As these healthy subjects are often
young, the goal of reducing CT dose is logical in this setting. However, the need for
detailed vascular analysis requires high quality axial and 3D imaging. Utilizing the
Discovery* CT750 HD with the dose reduction technology, ASiR*, helps our facility
achieve these goals.
Patient history
The patient is a 31-year-old female healthy subject who is being considered
for potential kidney donation.
Figure 1. Thin slice images demonstrate nice
detail for resolution of arteries.
Figure 2. Shows kidney patency and absence
of kidney masses.
Figure 3. Note the normal parenchymal vascular
anatomy for potential renal donors.
Figure 4. Displays normal vessels and perihilar
branching patterns for main renal arteries.
ABDOMINAL IMAGING
case st u dy
Dr. Joel F. Platt
Figure 5. MIP of right kidney (left); MIP of left kidney, deemed best choice for kidney donor (right).
Figure 6. VR of right kidney (left); VR of left kidney, deemed best choice for kidney donor (right).
Results
Axial and 3D image review revealed no renal masses, stones, or congenital
abnormalities. Vascular analysis revealed a single right renal artery with an early
perihilar branch and a single left renal artery. No venous abnormalities were detected.
Dose for the entire CT examination was 5.25 mSv§ of the CT study requiring dose
of only 2.47 mSv§.
Joel F. Platt, MD, is Director of the Abdomen Division
and Body CT and a Professor in the Department
of Radiology at the University of Michigan
(Ann Arbor). He is also on staff at the Veterans
Administration Hospital at the University of Michigan.
Dr. Platt received his medical degree from Boston
University School of Medicine. He completed his
residency training in diagnostic radiology at the
William Beaumont Hospital (Royal Oak, MI), where
he also held the position of Chief Resident, and his
fellowship training in Cross Sectional Imaging
and Interventional Genitourinary Radiology at the
University of Michigan Medical Center (Ann Arbor).
Dr. Platt is certified by the American Board of
Radiology and is a published author of numerous
research papers, peer reviewed publications, book
chapters, and scientific presentations. He is also
a national and international lecturer on the topic
of CT abdominal imaging. Conclusion
Based in large part on the CT exam results, the patient was selected as a suitable
kidney donor with the left kidney deemed the best choice for donation due to findings
for normal parenchymal and vascular anatomy. CT findings were confirmed at
surgery. Imaging information was obtained with a significant reduction in radiation
dose with high resolution imaging.
Discussion
Imaging evaluation of potential kidney donors represents a challenge, as these
are healthy, often younger, subjects in whom we would like to minimize radiation
exposure yet obtain high-resolution images to confidently identify and display
the pertinent vascular anatomy.
The Discovery CT750 HD can be utilized to help reduce radiation dose through dose
modulation using 260 to 380 mA. In this case we further reduced dose by scanning
at 100 kVp. In the past, these dose reduction technology resulted in poor image
quality; however, applying a novel reconstruction technique, ASiR, allowed image
quality to be maintained at a high level as required in this clinical setting.
As measured by mSv in this case, the radiation dose was more than 30% less
compared to our typical examination prior to the Discovery CT750 HD and ASiR.**
The Discovery CT750 HD provides a new standard in image clarity and lower dose.
The system enhances diagnostic imaging by providing new paths to clinical diagnosis
and treatment decisions. By using the Discovery CT750 HD, ASiR enables potential
renal donors to be scanned with low dose and provides a high-quality exam
on a healthy, young patient. n
About the facility
University Hospital is the University of Michigan
Health System’s hospital for adult patients. The
11-story, 550-bed hospital first opened its doors
in 1986. In its 1,796,262 square feet, the hospital
houses diagnostic equipment, clinical laboratories,
operating rooms, and inpatient and intensive
care units.
Obtained by EUR-16262 EN, using an adult abdomen factor
of 0.015*DLP
§
In clinical practice, the use of ASiR may reduce CT patient dose
depending on the clinical task, patient size, anatomical location
and clinical practice. A consultation with a radiologist and
a physicist should be made to determine the appropriate dose
to obtain diagnostic image quality for the particular clinical task.
**
A GE Healthcare CT publication • June 2011
45
case st u dy
spectral I maging
Characterization
of Renal Stones Using GSI
Shrinivas B Desai, MD, Director, Department of Imaging and Interventional Radiology1;
Rozil J. Gandhi, DMRD, DNB, Registrar in the Department of Radiology1;
and Joseph Sunith George, Clinical Applications Manager2
Patient history
A 39-year-old male presented with acute pain in left upper abdomen and flank
with no history of fever or hematuria. Ultrasound showed multiple calculi in
the left kidney with mild hydronephrosis. Patient previously underwent surgery
for right renal calculi. Urine biochemistry did not show any pus cells. Patient
was referred for non-contrast CT urogram.
Acquisition protocols
Scanner
Discovery* CT750 HD
FOV
50 cm
Findings
kVp
80 and 140
There were two calculi of average size, 1.3 cm, in the pelvis and middle calyx with mild
hydronephrosis of the left kidney. Both the ureters and right kidney were normal.
HU values of the stones were in the range of 450 to 490. Using a Gemstone Spectral
Imaging dual energy CT scan, the calculated effective atomic number of the calculi
was approximately 6.95 suggesting uric acid. The effective atomic number of uric acid
is 7.0. The spectral HU curve also showed a negative enhancement pattern.
These findings corroborated with the recurrent calculus disease in this patient.
Further biochemical studies conducted on the patient showed high serum uric acid
levels. Patient did not complain of joint pain.
Patient was diagnosed with gout, a disease of uric acid metabolism.
Discussion
Today in the practice of medicine, it is essential not only to treat the disease but
also its etiology. A non-contrast urogram using a conventional CT scan would not
demonstrate the constituents of the renal calculus. With the advent of dual energy
scanners, we can now determine the constituents of calculi with the additional
information, specifically calculation of effective atomic number, material density
overlay and preparation of histogram and spectral HU curve.
Uric acid calculi occur in disorders affecting uric acid metabolism. Hence, apart from
treating calculus, it is important to treat the basic metabolic disorder. Dual energy
CT scans can also detect oxalic, mixed calcium, struvite, and cystine calculi. Using GSI
we now have the ability to distinguish mixed non-uric acid calculi and characterize
their chemical composition.
By demonstrating the constituents of the calculus, GSI assists in guiding effective
patient management. n
Jaslok Hospital and Research Centre
GE Healthcare
1
2
46
A GE Healthcare CT publication • June 2011
spectral I maging
case st u dy
Dr. Shrinivas B. Desai
Figure 1. Histogram with effective atomic number of Stone (left); Spectral HU Curve shows negative
enhancement (right). Both are typical of uric acid calculus.
Shrinivas B. Desai, MD, is Director, Department
of Imaging and Interventional Radiology at Jaslok
Hospital and Research Centre (Mumbai, India).
He received his medical degree from Seth G.S.
Medical College and K.E.M. Hospital and
completed five post-doctoral fellowships
in imaging, MRI, and interventional neuroradiology
at the University of Manchester/Manchester Royal
Infirmary & Crumpsall Hospital (UK), Lariboisiere
Hospital (Paris), University of California San
Francisco, and Massachusetts General Hospital
(Boston). Dr. Desai has lectured internationally,
held various editorial board positions in academic
journals, including Editor-in-chief of the Indian
Journal of Radiology and Imaging, and authored
43 articles and eight book chapters.
Dr. Rozil J. Gandhi
Rozil J. Gandhi, DMRD, DNB, Registrar
in the Department of Radiology
Joseph Sunith George
Joseph Sunith George, Clinical
Applications Manager, GE Healthcare
Figure 2. Material density overlay showing uric acid in different color (above);
volume rendering of kidney stones (below). Calcium and uric acid are shown
in different colors.
Jaslok Hospital and Research Centre
A GE Healthcare CT publication • June 2011
47
case st u dy
NEURO IMAGING
CT Perfusion 4D
in Stroke Assessment
Howard A. Rowley, MD, Chief of Neuroradiology, Professor of Radiology,
Neurology and Neurosurgery, University of Wisconsin, Madison, WI, USA
Scan types performed:
Introduction
•
Unenhanced CT
•
CT angiogram (CTA) of carotid
arteries and circle of Willis (COW)
•
CT perfusion
GE Healthcare CT Perfusion 4D software offers fast, easy-to-use, fully automated
perfusion post-processing. A complete set of maps is generated including blood
flow, blood volume, mean transit time, IRF T0, and Tmax. Tmax reflects the transit
time to peak of the enhancement. It includes the delay of the arrival of contrast
to any given location from its arrival at the artery ROI (IRF T0). Interactive tissue
classification assists the user to determine the status of tissue based on blood
volume, blood flow, mean transit time, or Tmax maps. Interactive volumetric
functional maps allow for complete volumetric assessment to quickly localize
areas of interest (Figures 3 and 4). Smart Map offers improved image quality
and clarity, reducing spatio-temporal noise while preserving functional details
with repeatable results.
Acquisition Protocol
Scanner
LightSpeed* VCT
Scan protocol
CT Perfusion using
VolumeShuttle
Slice thickness
16 – 5mm images (8i x 2)
Coverage
80 mm
Rotation time
0.4 sec
Total
elapsed time
52.0 sec
Patient history
Total
exposure time
15.2 sec
A 57-year-old female fell at home, presents with left hemiparesis. tPA was
administered at outside hospital.
kVp
80
mA
500
Recon
algorithm
Standard
Right ICA clot (Figure 1B), Right MCA (M1) occlusion (Figure 1C) with acute right
hemisphere infarction (Figure 2).
SFOV
Head (32)
In this case, CT Perfusion assisted with assessing the response to the IV tPA
administered at an outside hospital and as a triage tool for consideration
of endovascular intervention. Despite the application of IV tPA, the patient
still had severe ischemia on arrival. n
Contrast Protocol
VolumeShuttle* provides extended 80 mm coverage at up to 24% less dose
with a single contrast injection compared to traditional 40 mm perfusion.
Diagnosis
Type of contrast 370 mg/ml strength
Contrast
injection rate
5 ml/sec
Total contrast
amount
40 cc
Saline
injection rate
5 ml/sec
Total
saline amount
30 cc
Figure 1. (A) Non Contrast
48
A GE Healthcare CT publication • June 2011
(B) CTA right ICA
(C) CTA right MCA
NEURO IMAGING
case st u dy
Figure 3. Sagittal Tmax, 5 mm slice thickness (top);
coronal Tmax, 5 mm slice thickness (bottom).
Figure 2. CBV, CBF (top, left to right); MTT, IRT T0 (middle row); Tmax, Tissue Classification (BV-Tmax) (bottom row).
Figure 4. Interactive Volumetric Map
demonstrating right MCA (M1) occlusion
with axial and coronal CBF.
A GE Healthcare CT publication • June 2011
49
case st u dy
P ediatric I maging
Low-dose CT Imaging
of CPAM for Surgical Planning
Jonathan R. Dillman, MD, Assistant Professor, and Peter J. Strouse, MD, Professor
of Radiology and Director, Section of Pediatric Radiology, University of Michigan
Health System, C.S. Mott Children’s Hospital
Acquisition protocols
DLP
15.98 mGy
kVp
80
mA
49-53
Noise index
33.6
CTDIvol
1.19 mGy-cm
Pitch
1.375:1
Scan range
I 87.5 top S 14.375,
0.625 increments,
2 mm thick (coronal
and sagittal)
ASIR
30%
8 cc dose, hand injected
0.62 mSv (using chest ICRP conversion
factor of 0.039)
Congenital pulmonary airway malformation (CPAM), which now includes both
congenital cystic adenomatoid malformation (CCAM) and pulmonary sequestration,
is a rare benign abnormality of lung development. They are commonly detected during
routine prenatal ultrasound examinations. Serial fetal ultrasound or MRI examinations
may be performed to assess for growth of the mass in utero during the last trimester
of pregnancy. Prenatal imaging also allows for the assessment of CPAM-related
complications, such as fetal hydrops (including heart failure) and mass-effect upon
other internal organs.
While ultrasound is most commonly the imaging study of choice in utero, a variety
of imaging studies can be performed soon after birth to provide further lesion
characterization and assist in surgical planning, including ultrasound, CT, and MRI.
Goals of imaging include assessing lesion location, extent, and whether or not the
lesion has a systemic feeding artery. If a feeding artery is present, its origin and
course should be established for surgical planning purposes. For example, if the
CPAM feeding artery is located below the diaphragm, the pediatric surgeon may
have to open the abdomen in addition to the chest.
At our facility, CT radiation dose has been minimized in various ways. One of our
most effective means of putting the ALARA (As Low As Reasonably Achievable)
principle into place has been our implementation of ASiR (Adaptive Statistical Iterative
Reconstruction) in conjunction with our Discovery* CT750 HD scanner. ASiR,* an
iterative approach to reconstruction, is capable of reducing image noise without
degrading anatomical integrity. This may allow for dose reduction in children while
maintaining diagnostic image quality.**
The following case highlights the importance of ASiR in pediatric imaging for a confident
diagnosis at low dose levels.
Patient history
A one-day-old full term (39 weeks) newborn with left-sided chest mass was originally
recognized during second trimester prenatal ultrasound. In utero, chest mass was
determined most likely to be a CPAM.
Immediately following birth, infant had respiratory difficulty. A portable chest
radiograph confirmed a mass within the left lower chest demonstrating significant
mass effect on adjacent structures (Figure 1), confirming the fetal ultrasound findings.
Patient also suffered a pneumothrax (collapsed lung), required intubation for
mechanical ventilatory support, and was referred to CT angiography (CTA) for further
characterization of the chest mass and to identify the location of any feeding vessel.
In clinical practice, the use of ASiR may reduce CT patient dose depending on the clinical task, patient size, anatomical location and clinical
practice. A consultation with a radiologist and a physicist should be made to determine the appropriate dose to obtain diagnostic image
quality for the particular clinical task
**
50
A GE Healthcare CT publication • June 2011
P ediatric I maging
case st u dy
of author
Impact of kVp andname
mAs
on dose
As radiologists know, when kVp is reduced,
mAs must be increased to reduce image
noise and maintain image quality.
However, such an increase in mAs does
info about clinic, etc.
not impact patient radiation dose in the
same manner as does a higher kVp.
Adjustments in kVp affect dose in an
exponential manner, while modifications
to mAs are linear. For example, doubling
the mAs doubles the dose, while an
increase from 80 to 140 kVp causes
a five-fold increase in the dose (assuming
a fixed mAs).1 Therefore, substantial dose
savings can be achieved by lowering kVp
even if it requires increasing mAs.
Figure 1. Initial portable anteroposterior (AP) chest radiograph demonstrates
a large mass (arrows) within the left lower chest with mass-effect upon mediastinal
structures, including the heart, esophagus, and descending thoracic aorta.
*
*
A
B
*
C
Reducing kVp while slightly increasing
mAs has additional potential benefits
for pediatric patients beyond radiation
dose reduction. A lower kVp level yields
more contrast between the bright and
dark areas on the image (increased
contrast-to-noise ratio); such increased
image contrast is desirable for certain
CT studies, such as CT angiography
and CT enterography. These low kVp
concepts have much potential and
require further study that is specific
to the pediatric population.
*
D
Figure 2. Four axial contrast-enhanced 2.5 mm CT images of the chest using 30% ASiR show a large
mass (arrows) filling the left hemithorax. The mass displaces the heart, descending thoracic aorta, and
esophagus to the right. Small areas of focal water attenuation within the mass (within the circles) were due
to secondary lymphectasia at pathology. An umbilical arterial catheter (blue*) is present within the aorta.
Reference:
Huda W, Vance A. Patient Radiation Doses from Adult and
Pediatric CT. AJR 2007; 188:540-546.
1
A GE Healthcare CT publication • June 2011
51
CASE STUDY
P ediatric I maging
Dr. Jonathan R. Dillman
Jonathan R. Dillman, MD, is an Assistant Professor,
Department of Radiology, Section of Pediatric
Radiology, University of Michigan Health System
and a pediatric radiologist at C.S. Mott Children’s
Hospital. Dr. Dillman graduated Summa Cum Laude
with a BS in Chemistry at Butler University
(Indianapolis, IN) and received his medical degree
from Indiana University School of Medicine
(Indianapolis, IN). Among his numerous awards and
recognitions is an RSNA Roengten Fellow Research
Award (2009), Best Poster Award, the 34th Scientific
Assembly of the Society of Uroradiology (2009), Best
Poster Award, the 38th Scientific Meeting of the
Society of Gastrointestinal Radiologists (2009),
John Caffey Award, Best Case Report, Society
for Pediatric Radiology 53rd Annual Meeting (2010),
and Mentor of the Year, Junior Staff, University of
Michigan Health System, Department of Radiology
(2010). Dr. Dillman currently serves on the editorial
board of Pediatric Radiology (Genitourinary Radiology).
A
*
*
*
*
B
Figure 3. Coronal reformatted and axial maximum intensity projection (MIP) images excellently depict
the presence of a large feeding artery (black arrows) to the mass (white arrows). Based on this finding,
the diagnosis of congenital pulmonary airway malformation (CPAM)/pulmonary sequestration was
confirmed. An umbilical arterial catheter (blue*) is present within the aorta.
Findings
Patient was diagnosed with a large CPAM/pulmonary sequestration involving the left
hemithorax with systemic arterial supply arising from the descending thoracic aorta
above the level of the diaphragm. The large mass caused rightward shift of mediastinal
structures, including the heart, descending thoracic aorta, and esophagus. Coronal
reformatted CTA images confirmed diagnosis of CPAM and clearly depicted a large
feeding artery (Figure 3B).
Patient underwent surgical resection the following day. Patient discharged after
two weeks and the infant was doing fine at his one-month post-surgery follow-up
clinical appointment.
Discussion
Dr. Peter Strouse
Peter Strouse, MD, is a Professor in the Department
of Radiology and Chief of the Section of Pediatric
Radiology at C.S. Mott Children’s Hospital. He
earned his medical degree from the University
of Michigan. Dr. Strouse completed two fellowships
at the University of Michigan, one in pediatric
radiology and the other in cross-sectional imaging.
He is certified in radiology as well as pediatric
radiology. Dr. Strouse’s clinical practice involves
most facets of pediatric imaging. His research
interests are pediatric abdominal imaging and
pediatric musculoskeletal imaging, particularly
applications of cross-sectional imaging
(sonography, CT, and MR) in these areas.
While ultrasound and MRI can also be used to diagnose and characterize CPAM and
sequestrations, both imaging techniques pose limitations. Ultrasound may be limited
in depicting the origin and exact course of a feeding vessel and is highly dependent
upon both the operator and the sonographic window, which can be impacted by air
in bowel loops in the upper abdomen and air in the lungs. MRI is commonly a 30
to 60 minute study that often requires sedation for pediatric patients. Medical
management of critically ill children in the MRI environment can also be challenging.
CT has historically been the imaging study of choice for the evaluation of CPAM—high
resolution imaging enables a confident diagnosis and, by depicting the feeding vessel,
provides the information required for surgical planning. CT allows for very rapid imaging
in an environment that is more conducive to managing critically ill children.
At C.S. Mott Children’s Hospital, concern regarding infant/pediatric radiation exposure
from CT dose has been partly allayed with the recent implementation of ASiR.
In situations such as this case where an infant’s medical condition is tenuous and
unstable, the rapid imaging capabilities of CT coupled with the low dose achieved
through ASiR enable us to make a very confident diagnosis while minimizing the
radiation dose imparted.**
In our experience, we have consistently achieved dose levels of about 1 mSv or lower
at 80 kVp with 30% ASIR in very young children, enabling us to image gently, minimize
any possible radiation-related concerns, and provide the necessary information our
pediatric surgeons require for surgical planning. n
In clinical practice, the use of ASiR may reduce CT patient dose depending on the clinical task, patient size, anatomical location and clinical
practice. A consultation with a radiologist and a physicist should be made to determine the appropriate dose to obtain diagnostic image
quality for the particular clinical task
**
52
A GE Healthcare CT publication • June 2011
Optima C T 6 6 0
technical inn o vati o n
ecomagination is based
on resolving the far-reaching
environmental problems
the world faces...the “eco”
represents both “ecology”
and “economy.”
– Naoya Monden
System Design Combines
High Performance with
Patient, Earth Friendliness
By Naoya Monden, Global CT Marketing Product Manager, GE Healthcare
In April 2010, GE Healthcare unveiled the Optima* CT660§, a next
generation, multi-slice CT system that is the first healthcare
product to be ecomagination and healthymagination
validated. Yet, the Optima CT660 is more than a system
designed to embrace these two initiatives. It inherits high
performance and clinical utility from other GE leading CT
systems, providing value in addition to placing strong
considerations on patient and Earth friendliness.
Optima CT660 is 510(k) pending at FDA. Not commercially available in the United States.
§
A GE Healthcare CT publication • June 2011
53
technical inn o vati o n
Optima C T 6 6 0
ecomagination
This initiative is based on resolving the far-reaching
environmental problems the world faces. The “eco” in
ecomagination represents both “ecology” and “economy.”
Companies and individuals are becoming increasingly
aware of environmental issues, and healthcare is no
exception. In fact, many hospitals now require
environmentally-friendly products.
Figure 1. Comparison of annual power consumption
attained with and without use of Energy Saving
Mode. “Active” is the use of Energy Saving Mode.
The Optima CT660 is the first CT system to be ecomagination
validated. The system is based on the concept that we
should contribute to the protection of the environment by
meeting the needs of clients requiring high energy efficiency
products. Specifically, the Optima CT660 Energy Saving Mode
can reduce CO2 emissions by more than 60%.
healthymagination
This initiative is based on the idea that more people should
be able to receive more affordable and high-quality medical
care, healthymagination is supported by three pillars: cost,
access and quality.
Cost translates to affordability
Figure 2. Sample room layouts for the Optima CT660.
Cost relates not only to the initial “price” of the system but
also to improvements in operating efficiency. Similar to the
energy saving mode of home electronics and appliances,
the Optima CT660 Energy Saving Mode can reduce electricity
cost by reducing extra power with a timer-controlled ON/OFF
switch. This mode allows energy savings up to 60% compared
with conventional systems. In monetary terms, this translates
to an annual savings of approximately ¥430,000 yen
(approximately $5,200 USD). To illustrate, the annual power
consumption figures attained with and without the use
of Energy Saving Mode are compared in Figure 1.
Reducing costs also means using less space. When an older,
conventional CT system is replaced with a newer system that
has a larger body or console, the siting cost is often higher.
For instance, if a single- or dual-slice CT system is replaced
with a 64-slice CT system, the CT room often needs to be
remodeled. However, in 90% of these cases, replacing
a current GE CT system with the Optima CT660 in the same
CT room avoids extending the room (see Figure 2).
Increasing the operating efficiency of a CT system requires
reducing the waiting time for tube cooling—and this often
requires a more expensive, higher capacity X-ray tube. Yet, the
Optima CT660 when equipped with ASiR—can substantially
reduce the burden on the X-ray tube leading to an increase
in operating efficiency. The use of ASiR may allow for scanning
at lower mA and less anode heat, thereby reducing tube
cooling limitations and potentially increasing the number
of examinations per day.
54
A GE Healthcare CT publication • June 2011
Optima C T 6 6 0
An increase in both examination efficiency and operating efficiency requires
patients to be rapidly examined during their stay in the examination room. While
multi-slice CT systems have substantially reduced scan time, patient positioning
time has not greatly improved. The Optima CT660 is based on the concept that
streamlining patient positioning is an integral component of the total solution.
It displays the name of incoming patients on the monitor screen, helps the medical
staff to set the patient smoothly and easily using the Default Patient Positioning
Function, and confirm image quality after the scan via fast recon speed.
Access to more people
technical inn o vati o n
Naoya Monden
Naoya Monden, Global CT Marketing Product
Manager, GE Healthcare
With a smaller footprint, the Optima CT660 can be sited in more facilities
constrained by a lack of space. Yet, these sites shouldn’t have to compromise
on quality or abandon acquiring a premium CT system. The Optima CT660 offers
both—a high-performance CT with a space-saving design. In fact, facilities can
reduce the installation area by up to 24% compared to conventional CT systems
(ratio to our products), or in a room that is at least 15 square meters (Figure 2).
The gantry is also downsized to save space, which also helps enhance staff
efficiency by opening up traffic lines. Patients also may feel less oppressed
in a small gantry when lying down on the CT table.
Enhancing the quality of care
Since the introduction of the multi-slice CT system in 1998, these systems have
progressed dramatically in the ability to generate thin-slices coupled with high
speed and clinical performance. As a result, CT angiography and cardiac examinations
have become widespread, if not routine in many healthcare institutions.
Today, CT exams offer high-quality, minimally invasive diagnostic techniques.
However, there is a greater awareness today of patient exposure to dose resulting
from a CT examination. Fortunately, GE Healthcare has been planning the
development of products based on the idea that both dose and image quality
are important factors in providing quality medical care. In 2008, GE led the
industry by introducing a state-of-the-art image reconstruction technique known
as ASiR (Adaptive Statistical Iterative Reconstruction) on the Discovery* CT750 HD.
Today, ASiR is available on the Optima CT660.
The Optima CT660
is based on the concept
that streamlining
patient positioning is
an integral component
of the total solution.
ASiR dose reduction technology may enable a reduction in pixel noise standard
deviation. This algorithm may allow for reduced mA in the acquisition of diagnostic
images, thereby reducing the dose required.**
As evident by the introduction of the Optima CT660, CT design and development
has reached a new turning point. It is possible for new generations of CT systems
to provide clinically excellent performance and while simultaneously being
“friendly” to patients, “considerate” to the Earth, and “healthy” to the hospital’s
financial management. n
In clinical practice, the use of ASiR may reduce CT patient dose depending on the clinical task, patient size, anatomical location
and clinical practice. A consultation with a radiologist and a physicist should be made to determine the appropriate dose
to obtain diagnostic image quality for the particular clinical task.
**
A GE Healthcare CT publication • June 2011
55
technical inn o vati o n
“Dexus provides
our facility with
the ideal workflow
environment,
allowing easy
collaboration
between colleagues,
while providing
access to data
from a workstation,
PACS, or home.”
– Dr. Richard A. Kane
A dvanced V is u ali z ati o n
One Seamless
Workflow Environment
By Laurent Stefani, Global Marketing Manager, Dexus, and Paul Edwards,
EMEA Product Manager, Dexus
One solution that streamlines image postprocessing. You asked for it, now
we’ve delivered it. GE Healthcare introduces Dexus,* a workflow environment that
optimizes reading experience and productivity from image acquisition through
results reporting. Built on the trusted GE AW and Centricity* platforms, Dexus links
imaging devices, clinical applications, and IT for access to advanced visualization
tools across modalities and patient care settings—whether the emergency room,
clinical area, or physician office.
As integral components of the Dexus environment, AW Workstation and AW
Server provide the portal to a broad portfolio of robust, easy-to-use clinical
applications. By streamlining post-processing and synergizing imaging techniques,
Dexus answers productivity needs across CT, MRI, PET, SPECT, and Interventional
modalities. The AW Server converts virtually any PC, laptop, or PACS desktop
to a 2D, 3D, and 4D post-processing workstation. This capability lets clinicians
remotely review and share images in real time, enabling close collaboration
with internal clinicians, stronger referring physician partnerships, more confident
diagnoses, and better patient care.
“For groups like ours with radiology sub-specialists available for consult, it’s very
useful that they can give their advice no matter where they are located,” says
Fred Cohen, MD, Clinique Médipôle Saint-Roch (Cabestany, France). “They could
be anywhere—they just use the software tools and provide feedback.”
56
A GE Healthcare CT publication • June 2011
A dvanced V is u ali z ati o n
Dexus environment leverages and maximizes technology
investments by seamlessly integrating with existing IT
infrastructure. For example, integration with an existing
RIS/PACS enables one-click access to the rich clinical AW
applications and the ability to leverage worklists, hanging
protocols, and reporting systems from one PACS desktop.
Integration to GE Centricity solutions provides instant access
to online post-processing and comparison of current and
prior exams, eliminating storage islands.
“Using this new version of the AW Server is very transparent
to workflow,” Dr. Cohen adds. “With one click I can go
directly to the server and begin reading cases without
entering additional passwords or other information.”
technical inn o vati o n
As part of the Dexus environment, the AW Workstation and
AW Server include a common user interface, optimized
protocols, review steps and tools for each clinical application
to guide simple image review and analysis.
With automated case preparation, studies are ready for
interpretation as soon as they are opened—the processing
is completed in the background. This includes bone removal
or coronary tree segmentation, tracking, and labeling.
“Dexus provides our facility with the ideal workflow environment,
allowing easy collaboration between colleagues, while
providing access to data from a workstation, PACS, or home,”
says Richard A. Kane, MD, St. Francis Hospital (Evanston, IL).
“With one click I can
go directly to the server
and begin reading
cases without entering
additional passwords
or other information.”
– Dr. Fred Cohen
A GE Healthcare CT publication • June 2011
57
technical inn o vati o n
A dvanced V is u ali z ati o n
Clinical solutions
Laurent Stefani
Laurent Stefani is the Global Marketing Manager,
Dexus, at GE Healthcare
As part of the Dexus environment, multimodality applications combine with
customized workflow for radiology, cardiology, vascular, oncology, and neurology—
providing one solution for virtually any care area.
For vascular studies, the Dexus environment provides a premium 2D/3D clinical
analysis tool that enables fast, routine review. It simplifies complex studies
such as plaque analysis, stenosis quantification, aneurysm measurement,
and bone segmentation. What’s more, analysis tools are available across the
enterprise so surgeons can fully interact with 3D images to precisely visualize
cardiovascular anatomy.
The Dexus environment also brings a breadth of new enhanced applications
in cardiology (see CardIQ Xpress Reveal article on page 6), neurology (see
CT perfusion article on page 50), and oncology. By bringing these new applications
together within the Dexus environment, AW and Centricity solutions come
together to facilitate follow-up by enabling instant access to priors and streamlining
comparisons over time.
Paul Edwards
Paul Edwards is the EMEA Product Manager,
Dexus, at GE Healthcare
The oncology application, OncoQuant, introduces a new focus on cross-modality
oncology. It builds upon the Dexus foundation and synergizes available information
to help clinicians diagnose, plan and guide interventions, and follow-up treatment.
“We can better collaborate with oncologists for monitoring patient progress
throughout the treatment cycle,” explains Professor Yves Gandon, MD, Chief
Radiologist of Medical and Functional Imaging, Hôpital Pontchaillou, CHU Rennes
(Rennes, France).
The software monitors tumor progression and response to treatment. With
automated and interactive access to quantitative information, clinicians can
visualize, track, and manage multiple lesions and patient exams over time.
“The solution can also have a more positive effect on the quality of measurements,”
Professor Gandon says. He believes OncoQuant helps with measuring and
reporting tumor response for the Response Evaluation Criteria in Solid Tumors
(RECIST) published rules.
Streamlined reading, simpler research, and streamlined workflow help enable
clinicians to deliver a more immediate diagnosis. Dexus brings the power of one
solution to medical imaging workflow so clinicians can access the information
they need—when and where they need it. n
58
A GE Healthcare CT publication • June 2011
S patial R es o l u ti o n
technical inn o vati o n
The Importance of Spatial
Resolution for High-quality
Cardiac CT Exams
By Vincent Norlock, Global Product Manager, and Jiahua Fan, PhD, Senior Scientist
Spatial resolution is important to the diagnostic quality
of a cardiac CT exam because it directly translates to
accurate, clear images—giving the physician the data to
help correctly establish the extent of coronary artery disease
(CAD) in those who have it, while clearing those without it.
Challenges to more accurate CCTA reading
Accurate estimation of CAD is challenged by the presence
of coronary calcium, stents, moderate-to-severe stenosis,
and the visualization of bypass grafts.
Calcium
Accuracy of CTA
Clinical trials have demonstrated that CCTA is a highly-accurate
means of excluding coronary artery stenosis and that
Coronary CT angiography (CCTA) is more likely to aid in the
detection of CAD and less likely to overestimate its extent
than some other testing modalities.
A highly calcified coronary stenosis can cause a “blooming”
effect in CT images. The blooming appears to expand the
boundaries of the stenosis into the surrounding voxels,
increasing the apparent size of the blockage. A 2009 study
using earlier, standard definition CT at Karolinska University
Hospital1 specifically called out the limitation on PPV caused
by vessel calcification. The study found that the “poor”
image quality segments were the result
of calcification and it was the main
reason for poor image quality in the LAD.
Images comparing earlier generations
of CT to the Discovery* CT750 HD
demonstrate that high resolution
scanning reduces the blooming effect
from calcium and aids in clearer
visualization of the vessel lumen (Figure 1).
This helps to overcome the appearance
of increased severity in lesions with highly
calcified plaque.
Figure 1a. Standard definition image of calcified
plaque and stent
Figure 1b. Reduced calcium blooming
with HD imaging
A GE Healthcare CT publication • June 2011
59
technical inn o vati o n
S patial R es o l u ti o n
Intracoronary stents
Vincent Norlock
Vincent Norlock is Global Product Manager
at GE Healthcare
The introduction of coronary stents provided a reliable means of combating the
effects of CAD. However, the artifacts potentially induced in the CT image by the
stent may enlarge the stent boundaries and thereby increase the apparent visual
size of the stenosis.
A study at Cornell University2 compared an earlier generation CT system to the
Discovery CT750 HD. This study reported that the Discovery CT750 HD not only
delivered impressive lumen area visualization, but also lower image noise. Both
of these factors are important for the physician to accurately assess the extent
of in-stent restenosis.
Moderate-to-severe stenosis
Jiahua Fan
The cited studies show that agreement with invasive angiography decreases
with moderate-to-severe stenosis. Previously, overestimation of the appearance
of the severity decreased the specificity, especially in smaller vessels.3
The Discovery CT750 HD has the ability to accurately image vessels as small
as 1 mm and provide the clinical reader with reliable information when diagnosing
stenosis in the distal vessels.
Bypass grafts
Jiahua Fan, PhD, is Senior Scientist
at GE Healthcare
The position and variation of coronary bypass grafts can add to the challenges
listed above. The Discovery CT750 HD delivers clear images for accurate
assessment of coronary anatomy and bypass graft conditions in a single scan.
The high resolution cardiac scan modes allow for sharp visualization of both
grafts and coronaries.
In clinical practice, the use of ASiR may reduce CT patient dose depending on the clinical task, patient size, anatomical location
and clinical practice. A consultation with a radiologist and a physicist should be made to determine the appropriate dose to obtain
diagnostic image quality for the particular clinical task.
**
60
A GE Healthcare CT publication • June 2011
S patial R es o l u ti o n
technical inn o vati o n
Comparing CT models
In 2010, the UK’s National Health Service’s ImPACT group published a report,
Market review: Advanced CT scanners for coronary angiography.4 The ImPACT group
gave each CT manufacturer requests for specific spatial resolution measurements
along with instructions on how they were to be acquired. Each company then
provided the ImPACT group at the NHS with results obtained from their own
in-house testing.
While not participating in this ImPACT report, GE made the same measurements
on the Discovery CT750 HD systems. A comparison of these results is shown
in Table 1A and Table 1B.
The data show Discovery CT750 HD has the ability to resolve 18.2 lp/cm in the
z-direction, allowing fine cardiac details to be seen. This high resolution is driven
by the properties of the GE Gemstone* detector and dynamic deflection of the
X-ray beam. When used in combination with GE’s ASiR* noise reduction technology,
the Discovery CT750 HD delivers high definition cardiac scanning at optimized
dose and noise performance.
Spatial resolution is not merely helpful in cardiac CT; it provides critical diagnostic
assessments. The data show the Discovery CT750 HD has the highest cardiac
spatial resolution of commercially available CT scanners. The Discovery CT750 HD
allows clinicians to visualize vessels as small as 1 mm and, in some cases
with ASIR** less than 1 mSv, in one exam they can count on.
References
L imitations of 64-detector-row computed tomography coronary
angiography: calcium and motion but not short experience.
Acta Radiol. 2009 Mar;50(2):174-80.
1
igh-definition multidetector computed tomography for evaluation
H
of coronary artery stents: comparison to standard-definition
64-detector row computed tomography. J Cardiovasc Comput
Tomogr. 2009 Jul-Aug;3(4):246-51
2
Diagnostic Performance of 64-Multidetector Row Coronary
Computed Tomographic Angiography for Evaluation of Coronary
Artery Stenosis in Individuals Without Known Coronary Artery
Disease: Results From the Prospective Multicenter ACCURACY Trial,
Journal of the American College of Cardiology Volume 52, Issue 21,
18 November 2008, Pages 1724-1732
3
Market review; Advanced CT scanners for coronary angiography,
CEP10043 March 2010. Available at http://www.impactscan.org/.
4
Comparison of specificity and sensitivity in cardiac imaging
Table 1A
Table 1B
Philips Brilliance™ iCT
Siemens SOMATOM
Toshiba Aquilion™ ONE
Definition Flash™
GE Discovery CT750 HD
Scan plane (x-y) spatial resolution, manufacturers specification [lp/cm]
HDS HDD HDDP
Reconstruction filter
CA CB CC CD
B30f B36f B46f
FCOI FCO3 FCO5
50% MTF
3.1 3.4 4.4 4.8
3.6 4.2 4.8
3.2 41 4.8
5.8
6.8
10% MTF
5.3 6.3 7.0 8.5
5.9 7.3 7.8
5.6 8.1 9.2
8.9
9.8 12.5
2% MTF
6.5 8.0 8.5 10.5
7.3 9.0 9.4
7.2 11.1 11.6
10.3 11.2 14.8
CA~0.95; CB&CC~0.9;
CD~0.8
~0.9
Data not available
0.92
Off-center resolution
(125 mm):
Ratio off-center/center
6.2
Longitudinal (z) spatial resolution, manufacturer’s specification [lp/cm]
50% MTF
5
6.5
4.1
6.8
10% MTF
8
12
8.1
13.7
2% MTF
12
15
11.1
18.2
Source: Table 1A. Market review; Advanced CT scanners for coronary angiography, CEP10043 March 2010; Table 1B. GE Healthcare.
A GE Healthcare CT publication • June 2011
61
technical inn o vati o n
S patial R es o l u ti o n
Alyssa Nowak
Alyssa Nowak is CT Product Development
Specialist at GE Healthcare
How did GE make these measurements?
Using the ImPACT assessment guidelines, GE Engineer Priti Madhav created
a testing protocol for Discovery CT750 HD. Together with Alyssa Nowak, CT
Product Development Specialist, the in-plane and longitudinal resolution of both
axial and helical cardiac scans was evaluated.
In-plane (x-y) measurements were made with a GEPP phantom. Longitudinal (z)
measurements in cardiac axial mode were made using a slope 4-wire phantom
while a gold foil phantom was used for cardiac helical measurements.
Priti Madhav
These measurements not only characterize the spatial resolution of the
CT hardware but also the image reconstruction kernels used. In our tests,
we measured only those kernels normally used for cardiac scanning. n
Priti Madhav is Lead Engineer, System Physics
and Image Quality, at GE Healthcare
Figure 2. GEPP Phantom (left), Gold Foil Phantom (center), Slope 4-wire Phantom (right)
In clinical practice, the use of ASiR may reduce CT patient dose depending on the clinical task, patient size, anatomical location
and clinical practice. A consultation with a radiologist and a physicist should be made to determine the appropriate dose to obtain
diagnostic image quality for the particular clinical task.
**
62
A GE Healthcare CT publication • June 2011
Ultra - l o w D o se
technical inn o vati o n
The Model-based Paradigm:
A New Frontier
in Image Reconstruction
By Jean-Baptiste Thibault, PhD, Principal Scientist, CT Systems – Advanced Algorithms
Advancements in CT have increased dramatically during
the past 10 years, offering a more effective non-invasive
technique for examining patients without having to resort
to exploratory surgeries that were once routine clinical
practice. The growing importance of CT as a diagnostic tool
increases the need for solutions that improve diagnostic
information yet lower radiation to patients.
However, these advancements in CT technology are no
longer driven solely by hardware components. Software—
including reconstruction and image processing—is an
important element to diagnostic accuracy.
Realizing this, GE Healthcare has developed a powerful class
of new reconstruction techniques designed to explicitly include
the modeling of data statistics into the reconstruction. ASiR,*
introduced in 2008, first demonstrated the potential of
advanced statistical algorithms. In 2011, Veo*§ builds upon
the foundation laid by ASiR by now including accurate
modeling of X-ray physics and system optics. This robust,
full model-based iterative reconstruction was designed
from the ground up to enable improved image quality
and to enhance imaging performance even under very low
mA scenarios. Veo may enable diagnostic images at lower
dose levels.**
Limitations of prior reconstruction methods
Since the introduction of clinical CT systems in the late
1970s, the same analytical Filtered Back-Projection (FBP)
algorithm has been used as the basis of commercial CT
reconstruction until now. To make the mathematics
manageable, many simplifications and assumptions were
made, including the following: the measured signal contains
no error due to photon statistics or electronic noise; the
X-ray tube focal spot is an infinitely small point; the detector
is also formed of points located at the center of each cell;
and the reconstructed voxel is a point with no shape or size.
As a result of these geometric and noise assumptions, FBP
is an imperfect process.
First and most important, FBP ignores that the projection
data are corrupted by quantum and electronic noise
during acquisition. Instead, it may propagate and sometimes
amplify noise into patient images, creating streaks and
artifacts, which may hide pathology and valuable diagnostic
information. This can can make low-dose imaging with
standard reconstruction techniques a significant challenge.
The remaining three assumptions of FBP all deal with
the geometry of system optics. While necessary from
a mathematics point of view, these assumptions lead
to a trade-off in image quality simply due to the fact that
they do not give an accurate description of the data
acquisition process in the CT system.
Model-based iterative reconstruction
Anticipating the need for high-quality, low-dose imaging
in modern scanners, GE’s quest to develop a reconstruction
algorithm that is modeled after system statistics and “real”
optics, or the true status of the CT system, began in 2001.
This led to the introduction of ASiR by GE Healthcare, the
first breakthrough commercial iterative reconstruction
algorithm for CT. By focusing on quantum and electronic
noise in projection space, ASiR was able to deliver significant
dose reduction potential in a computationally efficient
manner and greatly improve image results.
Veo is 510(k) pending at FDA. Not commercially available in the United States.
§
A GE Healthcare CT publication • June 2011
63
technical inn o vati o n
Ultra - l o w D o se
With Veo, our goal was to add geometric accuracy and X-ray physics modeling
to attain the highest level of image quality regardless of complexity and length
of time to develop, test, and implement. We believed that improvements in
modern computing would continue to progress to the point where the complex
reconstruction process could be performed in clinically acceptable times.
Jean-Baptiste Thibault
An important requirement for the reconstruction algorithm was to model accurately
the system optics and the X-ray physics of data acquisition for a more realistic
representation of the data acquisition process. This is important because system
response changes depending on the location of each image element in the field of
view relative to the scanning trajectory. The reconstruction algorithm also had to
be adaptive—that is, adapt and react to the different types and densities of tissue,
for instance, bone and soft tissue—including the ability to optimally reduce noise
and preserve details in different areas, such as edges (high frequency content) and
homogeneous regions (low frequency content). Finally, the algorithm provides a
measure of confidence in each acquired data point—the data statistics—based
on the physics of data acquisition to allow for independent control of noise in the
reconstruction process. The latter is a unique feature of the Veo algorithm.
Jean-Baptiste Thibault, PhD, Principal
Scientist, CT Systems – Advanced Algorithms,
GE Healthcare
As a result, Veo solves the fundamental problem of image reconstruction (to produce
images that most accurately match projection data) by directly optimizing the
System optics
Raw data
Final image
rithm
o
ive alg
Iterat
The GE difference
•
•
Desired image behavior
Data statistics
Figure 1. Advanced model-based approach to CT reconstruction.
64
A GE Healthcare CT publication • June 2011
Ultra - l o w D o se
technical inn o vati o n
constrained function in Figure 1 for optimal image quality. This is different from
other proposed approaches that combine sinogram processing and image filtering
as separate steps to reduce noise, sometimes with unstable or unpredictable
results. Instead, the mathematical formulation for Veo ensures that the desired
images are obtained at the end of the iterative process.
With Veo accounting for the modeling of data statistics, X-ray physics, and system
optics, the reconstruction performance was the next hurdle. Thanks to partnerships
among GE, IBM, and Intel that led to optimized hardware and software platforms,
a ten-fold increase in reconstruction performance was achieved in 2007. When
coupled with further advances in iterative optimization algorithms pioneered
by GE Healthcare, true of model-based reconstruction of clinical patient exams
became a reality when Veo was introduced on the Discovery* CT750 HD.
Relaxing the trade-off between spatial resolution and noise
Before ASiR and Veo, radiologists learned to read through noise to identify
anatomy and pathology. With FBP, higher spatial resolution is accompanied
by higher image noise. On the contrary, a statistical method like Veo operates
to explicitly reduce or eliminate image noise with the goal of obtaining optimum
image clarity. It challenges the common trade-off to improve resolution while
simultaneously reducing noise significantly and improving contrast.
This is a significant advantage of Veo relative to conventional FBP reconstruction.
With advanced noise and physics modeling, Veo can accurately estimate the
contributions from photon noise to the projections after dense bone and metal
attenuation and significantly reduce shading artifacts (Figure 2). It also provides
high spatial and contrast resolution around different tissue types and densities
(Figure 3).
Veo represents a new foundation for CT image clarity, where improved model
accuracy results in better images, featuring previously unattainable levels
of combined noise reduction, resolution gain, improved contrast, and artifact
suppression. This powerful model-based iterative reconstruction extracts more
information from the acquired signal and opens the way to a bright future
for low-dose, high-quality images. n
C
Figure 2. FBP Reconstruction (top) and
Veo Reconstruction (bottom) of a low-dose
abdomen-pelvis: Veo shows a clear
improvement in the identification of renal
nodules and the reduction of shading artifacts
originating from the metal hip implant.
D
In clinical practice, the use of ASiR may reduce CT patient dose depending on the clinical task,
patient size, anatomical location and clinical practice. A consultation with a radiologist and a
physicist should be made to determine the appropriate dose to obtain diagnostic image quality
for the particular clinical task.
**
A
B
Figure 3. Comparison of FBP (A, C) and Veo reconstruction (B, D) showing
significantly reduced noise combined with improved detail for a stent
in the carotid artery.
A GE Healthcare CT publication • June 2011
65
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techn o l o gist ’ s c o rner
Techniques to Lower CT Dose
By Patricia Zoltowski, Clinical Educator, CT Global Marketing
Dose management must be a high priority not only
for Coronary Computed Tomography Angiography (CCTA)
exams but also for routine studies. As such, it is important
that technologists know the available options on the
CT scanner to utilize dose reduction techniques.
In fact, due to recent events concerning patient overexposure to CT dose in 2010, the FDA launched The
Initiative to Reduce Unnecessary Radiation Exposure from Medical Imaging. Through this initiative, the
“FDA is advocating the universal adoption of two principles of radiation protection: appropriate justification
for ordering each procedure, and careful optimization of the radiation dose used during each procedure.
Each patient should get the right imaging exam, at the right time, with the right radiation dose.”1
To ensure the right radiation dose, there are several actions that radiological technologists can employ
to offer dose-reduction strategies in the imaging suite. These include the following:
Dose reduction strategies
1. Proper patient positioning on a CT scanner table is the first step to assure use of dose saving options.
Higher noise images can occur when patients are not well centered in the scan field of view (FOV). By
positioning the body at isocenter, the need to increase mA to compensate for the noise is eliminated.
2. Utilization of BMI charts. Technologists can reduce dose without image degradation by observing the
patient’s weight and size. This can be based on the patients’ body habitus, or Body Mass Index (BMI).
Some radiologists are suggesting that if a patient’s BMI is less than 30, a lower kVp and mA can be used.
3. Reducing mA and kVp. With mA, the relationship is directly proportional, meaning if mA is reduced
by half, the corresponding dose is reduced by half. If kVp is reduced, the relationship is non-linear
(exponentially lower). For example, if you reduce kVp from 120 kVp to 100k Vp (16.5% reduction
of kVp) the result is a dose reduction of almost 40%.
4. Limiting the Scan Length/coverage to the ROI. Limiting the coverage of the scan will also help
reduce dose. More accurately selecting the coverage area limits the start and end location and,
therefore, reduces dose.
5. 3D Dose Modulation (AEC). AEC is an option with the ability to optimize dose to achieve the user
inputted image quality (IQ) desired. When set up properly this may provide a dose reduction compared
to a fixed mA scan set up to deliver the same IQ at the highest attenuation locations. Before the scan,
the technologist selects the desired Noise/IQ. The scanner then automatically tailors the exposure
based on the scout and body habitus of the patient.
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A GE Healthcare CT publication • June 2011
techn o l o gist ’ s c o rner
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Dose management techniques on GE scanners
In addition to the actions outlined above, GE provides
several dose minimization strategies that are built directly
into the scanners. Most of these techniques have been
available on GE scanners for many years.
1. AutomA and SmartmA. GE Healthcare’s answer for 3D
Dose Modulation (AEC) is AutomA* and SmartmA*. AutomA
optimizes the mA for each axial, helical, and cine scan.
The benefit is to maintain a constant photon exposure
for consistent image quality while providing dose
reduction to the patient. AutomA changes mA across
the z axis while SmartmA changes the mA across
the x/y axis within a slice.
2. ECG modulated mA. When using retrospective gating
in the cardiac helical scan mode, radiation dose can be
reduced with the use of ECG Modulation. ECG Modulation
allows for the variation of mA across the cardiac cycle
depending on the phase of the cardiac cycle where
maximum mA is applied and minimum mA is modulated
across the rest of the phases. The range of phases for
peak mA is prescribed by the user. Depending on the
phase range selected for maximum mA, the dose
reduction for a cardiac helical scan can be reduced.
This technique is not only used on cardiac scans but also
on gated PE studies, gated aorta studies and Triple R/O
exams to alleviate motion from the heart.
3. P
rospective gating. Prospectively gated CCTA utilizing
GE Healthcare’s SnapShot Pulse dramatically reduces
radiation exposure up to 83% with heart rates below
65 bpm compared to a low pitched helical cardiac
acquisition. This is due to the X-ray being on during
the prescribed cardiac phases only, meaning that data
is not collected continuously across the cardiac cycle.
This is an alternative to helical acquisition using axial
step-and-shoot mode to acquire images during a
specified phase of the heart cycle. This technique
captures images of the heart and arteries using a series
of three to four exposures taken in a step-and-shoot
fashion. The X-ray is turned on only during the prescribed
cardiac phases and is turned off when the table moves
to the next location.
Figure 1. 3D Dose Modulation.
Figure 2. Illustration to show when peak (maximum) mA is applied.
Figure 3. Technologist user interface
Figure 4. Prospective gating – The pink box displays the specific phase
of the cardiac cycle when the X-ray is turned on.
A GE Healthcare CT publication • June 2011
67
bey o nd the scan
Patricia Zoltowski
techn o l o gist ’ s c o rner
3. B
owtie Filters. Bowtie beam shaping filters attenuate off-axis rays to minimize
dose and reduce X-ray scattering effects. GE offers different bowtie filters to
more closely match the body part being imaged. Up to three different bowtie
filters can be selected to more closely match the body part being images (head,
body, heart) and patient size (adult or pediatric). Bowtie filters maintain a more
uniform X-ray field at the detector to minimize the surface dose and reduce
X-ray scatter. The bowtie filter results in an overall improvement in CT number
accuracy, image uniformity, low-contrast detectability and imaging dose.
Patricia Zoltowski, BS, RT (R), is CT Clinical
Educator at GE Healthcare
Figure 5. Bowtie beam shaping filter.
4. Reconstruction. ASiR* (Adaptive Statistical Iterative
Reconstruction) is a new reconstruction technique that
may enable reduction in image noise (pixel standard
deviation). By reducing image noise, ASIR in-turn may
allow a technologist to reduce the dose required to
produce diagnostic-quality images. ASiR may also enable
improvement in low contrast detectability. In clinical
practice, the use of ASiR may reduce CT patient dose
depending on the clinical task, patient size, anatomical
location, and clinical practice. A consultation with a
radiologist and a physicist should be made to determine
the appropriate dose to obtain diagnostic image quality
for the particular clinical task.
Figure 6. Cardiac filter selection on CT Scanner.
Reference:
Available at http://www.fda.gov/Radiation-EmittingProducts/RadiationSafety/
RadiationDoseReduction/ucm199904.htm
1
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A GE Healthcare CT publication • June 2011
5. C
ardiac noise reduction filter. Selecting the appropriate
cardiac noise reduction filter may also enable the
technologist to further reduce dose while preserving
the same image quality. This option will not automatically
reduce dose. The cardiac noise reducing and edge
preserving filters are labeled C1, C2 or C3. Once the
user chooses the appropriate filter, the mA can then
be reduced manually.
In addition to utilizing the tools and techniques addressed
in this article, it is important for each facility to implement
a QA program to review scanning protocols, enact the
utilization of pediatric protocols and, most important, as the FDA
states in its initiative, ensure the appropriateness of use in
CT scanning. To further ensure the safety of patients, facilities
should support the continuing education of their technologists,
including initial and ongoing certification in CT. n
D o se S trategy
Working Together
Towards the Sub-mSv
CT Exam
By Kenneth Denison, PhD, CT Dose Leader
Radiation dose from CT. It’s a concern that many share—clinicians, manufacturers,
patients, and government agencies. While recent events have highlighted the
importance of reducing medical radiation dose in the general population and news
media, it is an issue that GE Healthcare has addressed for over 30 years.
bey o nd the scan
Kenneth Denison
Kenneth Denison, PhD, is CT Dose Leader
at GE Healthcare
At GE Healthcare, patient safety is our primary concern.
Consider the sheer number of CT exams performed each year. According to the
latest CT census data from IMV1, an estimated 68.7 million CT procedures were
performed in 7,640 hospital and non-hospital sites in 2007. This represents a
growth of approximately 8% since 2003. During this same time, multi-detector CT
became the standard of care in many clinical care areas, causing some to raise
concerns over the potential for inappropriate radiation from CT imaging.
There is a certain irony with the use of CT imaging. Medical radiation in imaging
technologies has enabled major medical advancements in the accurate detection
of disease, the delivery of treatment, and the evaluation of treatment efficacy.
They allow physicians to more easily visualize and characterize disease without
the need for invasive procedures.
In fact, a recent study by Columbia University Professor of Business Frank
Lichtenberg and based on data from the National Cancer Institute and Thomson
Medstat, found that medical imaging innovation accounted for 40% of the decline
in cancer deaths in the US over the last decade. And, CT imaging has been called
one of the most significant advances in the history of healthcare.
Medical radiation
in imaging technologies
has enabled major
medical advancements
in the accurate
detection of disease,
the delivery of treatment,
and the evaluation
of treatment efficacy.
Yet, along with these powerful contributions to the quality and advancement
of healthcare delivery, the issue of medical radiation also requires that physicians,
healthcare facilities, and manufacturers work together to develop and evolve
effective processes and systems to promote its appropriate use.
A GE Healthcare CT publication • June 2011
69
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D o se S trategy
At GE Healthcare, we believe that this responsibility goes
beyond the development and evolution of dose-reduction
technologies. We support a comprehensive approach that
takes into account the environment in which such equipment
is used and those who are responsible for its implementation.
We believe that a collaborative, system-wide approach
to creating a dose-conscious healthcare system will help
promote positive change—without limiting the progress
of healthcare and its stewards to serve their patients well.
Starting with research
Promoting the best use of CT imaging is an important first
step in lowering medical radiation dose. We believe, as a
manufacturer, it is not enough to just build a better machine
and hope it is used properly—we also have an invested stake
in promoting the optimal use of the technology we make
to help support the best patient care.
To that end, GE Healthcare is spending millions of dollars
to fund research to identify and help define the standards,
practices, and metrics required for any healthcare provider
to implement a safe, effective, and efficient CT imaging
program. To conduct this research in an independent and
unbiased manner, GE has provided a grant to a third party,
non-profit research organization focused on improving
patient safety. Through collaboration with multiple physician
researchers across multiple care settings—from small, rural
hospitals to the largest, most complex academic medical
centers—the organization will collect and analyze procedural
data, practices, protocols, processes, and financial and
outcomes data for the full imaging cycle in order to develop
a consensus on the “is state” and the “best achievable state”
of CT care.
The objectives of this research are to:
• Provide a forum for endorsement;
• Document the current “is state” of CT imaging across
multiple care settings;
• Define the “best achievable state” across multiple
care settings;
• Identify opportunities to help close the gap between
the “is” and “best achievable” states;
• Address the opportunities for high-performance
improvement around the full loop from patient assessment
for imaging ordering, image execution, and reporting
in the new value-based purchasing environment.
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A GE Healthcare CT publication • June 2011
Driving this research is the idea that high-performance
imaging programs ensure that the right procedure is done
in the right way at the right time with the right dose, and the
correct interpretation is accurately and quickly communicated
to the patient. The results of this project will be published
in the literature so that all stakeholders can benefit from them.
GE Healthcare believes that high-performance imaging
programs occur only when a system-wide approach is taken
and only when the program correctly addresses three
key dimensions:
Leadership—the policies, processes, metrics, performance
systems, culture, and change management that are
characteristics of high performers;
Practices—the use of the best practices including
appropriateness criteria, triage, protocol development,
and scanning procedures; and
Technologies—the use of the right CT devices, dose-lowering
features, and dose reporting/tracking/monitoring software.
A key output of the program will be assets to help healthcare
providers assess their current leadership, practices, and
technologies and assess gaps in the four “A’s”: awareness,
accountability, ability, and action. Are we aware of
performance gaps, best practices, and the benefits and
risks of current and new technologies? Are there leaders or
clinicians accountable to close gaps and adopt best practices?
Do our leaders, clinicians, and staff members have the
ability and know-how to close the gaps and ensure patient
safety? Are we consistently taking action to close our gaps?
Solutions to close the gap
At GE Healthcare, our intent is to help our customers build
high performance imaging programs using this system-wide
approach. Our focus is not only on the CT scanning technology
we build, but on additional products and services that will
help our customers build better imaging programs.
Today, GE Healthcare is working on DoseWatch, a new IT
application that is expected to be commercially available
this year. The goal is to allow clinicians to track, report, and
monitor dose from multiple manufacturers and multiple
imaging devices, including CT, interventional, mammography,
and R&F. Our customers will have one source of radiation dose
information that can be used to optimize their performance,
monitor sensitive patients, and help prevent errors.
D o se S trategy
Also look for Dose Check coming to GE Healthcare CT scanners this year. In
response to an FDA request that stemmed from the Agency’s investigation into
recent incidents of overexposure, the Medical Imaging and Technology Alliance
(MITA)—a trade group comprised of the five major manufacturers of CT systems—
developed Dose Check, an industry standard to provide healthcare providers
with tools to set limits on the amount of radiation that will be delivered during
CT scans (see sidebar).
The objective of Dose Check is to ensure there are notifications and alerts
provided to the operator before a CT scan is prescribed above pre-determined
radiation exposure levels.
How low can dose go?
In addition to adopting the new Dose Check standard, GE will continue its 30-year
commitment to developing technologies that can lower dose without impacting
image quality. Over 900 installed GE CT scanners today are equipped with ASiR*,
a proven technique for lowering dose while maintaining image quality. ASiR has
been used in over 7 million exams to date.
Our next generation dose reduction technique, Veo§ shows great promise
in providing exceptional image quality at even lower doses. Available today
in markets outside the US, Veo is helping clinical users move toward our shared
goal of routine, sub-mSv CT exams. Early adopters are seeing great results with
Veo (see page 34) and we look forward to continuing to share their clinical cases
with you in future issues of CT Clarity.
And there is still more to come. At GE Healthcare we recently completed our
annual strategic planning process. Featured prominently in this year’s plan are
still more dose-lowering features for our CT devices and new services to help
build a high performance CT imaging program. We look forward to telling
you more about these exciting developments in future CT Clarity articles.
Lowering dose isn’t just about building a better device. It’s about working together,
to ensure that every patient receives the right exam, at the right time, and
at the right dose. n
Reference:
IMV 2007 CT Market Summary Report, IMV Medical Information Division, Des Plaines, IL. Available at www.imvinfo.com.
1
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Dose Check
Dose Check is a NEMA XR-25 standard
defined in conjunction with MITA and
other stakeholders that notifies and
alerts the operating personnel, generally
technologists, when the estimated dose
index is above the value defined and
set by the operating group, practice,
or institution. It is part of a department’s
Quality Assurance process providing
tools for auditing and tracking scans
where Alert or Notification values have
been exceeded.
Notification Value (NV) is the dose index
that is above the institution’s established
range for the protocol. NV is intended to
be set at a level that would be considered
above “routine” or “normally expected”
dose, but not at such a high level as to
pose a significant risk to the patient.
Depending on the patient size or
imaging need it may be appropriate to
scan at a value above the notification
value in order to achieve the diagnostic
intent of the exam. Scanning is possible
with no further authorization if the NV
level is exceeded. GE encourages sites
to establish appropriate notification
values for all scanning. The AAPM
has published a list of reference NV’s
on its website at www.aapm.org.
Alert Value (AV) is a value established
by the institution which will trigger an
alert when the prescribed imaging series
would cause the dose accumulated over
the course of the exam to exceed this
value. It is checked at exam level
according to system presets and requires
a user with authorization to confirm a
scan exceeding this value. Manufacturers
have pre-populated the AV at 1,000 mGy
in accordance with FDA suggestion.
In clinical practice, the use of ASiR may reduce CT patient dose depending on the clinical task, patient size, anatomical location
and clinical practice. A consultation with a radiologist and a physicist should be made to determine the appropriate dose to obtain
diagnostic image quality for the particular clinical task.
*
Veo is 510(k) pending at FDA. Not commercially available in the United States.
§
A GE Healthcare CT publication • June 2011
71
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E D U C AT I O N
CT Clinical Education in the US,
Europe, Middle East,
and Africa
US Education
The CT Masters Series education consists of intensive
and comprehensive courses developed and taught by expert
radiologists, cardiologists, and technologists in multi-slice
CT and advanced CT applications.
Current offerings:
• Cardiac CT for Physicians*
• Dose Reduction & Scanning Techniques
• Cardiac CT for Technologists
• Gemstone Spectral Imaging
• Peripheral CT Angiography
• Advanced Neuroimaging Techniques
*
Endorsed by
*
• CT Colonography
What’s New!
Introducing the New Gemstone Spectral
Imaging Workshop with James P. Earls, MD
This workshop is designed to provide radiologists and technologists with an in-depth
understanding of how Gemstone Spectral Imaging (GSI) can be used routinely to aid
in the diagnosis of patients and to assist clinicians with evaluating incidental
or indicated findings.
Special
Introductory
Offer:
50% Tuition Discount
when paying with a credit card
or 2 for 1 if paying with
a GE Order Number.
The following topics will be covered:
• Physics and theory of dual energy;
• Benefits of monochromatic and spectral images;
• Clinical applications of GSI;
• Scanning procedures – protocols, presets, parameter choices,
reconstruction options;
• Artifact reduction tools; and
• Hands-on practice of the GSI Viewer on the Advantage Workstation.
72
A GE Healthcare CT publication • June 2011
For more information and to register
for a CT Masters Course please visit
www.gehealthcare.com/gectmasters
or contact the CT Training Coordinator
at 262-312-7148.
E D U C AT I O N
bey o nd the scan
“I am grateful for the opportunity to have attended the GE Masters Series GSI course taught by Dr Earls.
During the 3-day course I learned the principles behind spectral imaging, and the current applications
that have been developed or are in development. The hands-on instruction, both in scan acquisition
and workstation image analysis was well done and very helpful. I enjoyed the open interactive style
of education with ample opportunity to ask questions and practice skills. I would recommend this
course to anyone interested in adding dual energy CT scanning to their service repertoire”.
– Larry Reif, MD, United Hospital System, Kenosha, WI
EMEA Education
Integrating dose reduction across clinical
education curriculum
GE Healthcare’s CT Clinical Education team is integrating dose reduction techniques
across its range of different customer training offerings.
This starts with the initial on-site applications visit through various customer support
revisits. During these sessions, the CT clinical education specialist will work with
the customer to optimize their protocols using the latest dose reduction technology
where appropriate to deliver high image quality at the lowest possible dose.
Dose optimization courses
Participants will learn about CT radiation dose, including measuring dose
delivered to the patient and CT dose optimization methods across the spectrum
of patient examinations. The focus is to help users understand how changing
scan parameters can affect both image quality and dose delivery applying
ALARA principles.
Low dose cardiac training
Participants will learn all the aspects of cardiac CT from image acquisition
to post processing techniques on the Advantage Workstation. The course will
focus on helping users get the most from the technology while simultaneously
reducing patient dose. The agenda includes a visit to a CT Department view
Cardiac examinations being performed in a hospital setting. Courses are SCCT
accredited and delivered in Plymouth UK.
Find the latest information
on training for Europe, Middle
East, and Africa at:
http://www.gehealthcare.com/
clinicaleducation
AppsLinq™ – Remote training and support
Picture a clinical education specialist by your side whenever you need it.
AppsLinq is a remote service application for troubleshooting and training
that will help your CT department solve application-related problems, improve
efficiency, and develop critical new skills. n
A GE Healthcare CT publication • June 2011
73
GE Healthcare
Computed Tomography
Great care
by design.
No company has done more to bring low dose to
patients than GE Healthcare. That’s no coincidence —
in fact, it speaks to the single purpose that guides our
business: helping you deliver high-performance care.
Our approach is built upon a foundation of low-dose
technology. But it also encompasses the best
practices and industry exposure we’ve amassed for
decades. The result is a true end-to-end partnership
designed to help you provide lower dose patient care,
more efficiently, and more effectively.
You’re here to deliver high-performance care.
We’re here to help you do it.
www.gehealthcare.com/LowDoseCT
ASiR*
Lower image noise while
improving low contrast
detectability and image quality.
Partnership
Decades of CT experience have made
us a strong, dedicated partner who
understands healthcare’s complexities
Gemstone* Spectral Imaging
Expand information for clinical
diagnosis and workflow.
© 2011 General Electric Company
*Trademark of General Electric Company.
CT-0470-05.11-EN-US