Download Ultrasound - Sudan University of Science and technology

‫بسم هللا الرحمن الرحيم‬
Sudan university of science and
technology
College of medical radiological science
Diagnostic radiologic technology
department
4th level
Seminar about:
Musculoskeletal System
Ultrasound
Table of Contents:•Introduction
•Equipment
•Ultrasound physics
•Technique
•MSK ultrasound artifacts
•Musculoskeletal ultrasound benefits
,limitations, and risks
Introduction
The Problem of the study:• Bone diseases usually differentiated and
confirmed by laboratory investigations which
were invasive and expensive , so we need
another non invasive, cheep and available tool
for diagnosing.
Objectives:• To evaluate the roe of ultrasound in
demonstrating musculoskeletal diseases.
• To identifying the a features of the new
technology which applied by ultrasound.
• To demonstrate ultrasound findings in each
pathology .
Introduction:
Now a days radiology was grown faster and
there were anew machines and applications
were discovered routinely.
The Sound:
It is a mechanical wave that is transmitted
through medium ( e.g. , air , water, meta, or
tissues).It is composed of three types:
I. Ultrasound
II. Hearing sound
III. Infra sound
Ultrasound:It is a mechanical energy transmitted through
a medium by pressure wave.
History of US:• Its discovered by Jacques and Pierre Curie in
1880, was useful in transducers to generate
and detect ultrasonic waves in air and water,
also its frequencies greater than 20 kHz.
Common indications for MSK ultrasound:• assessment of ligament and/or tendon tears.
• investigation of articular disorders involving cartilage.
• assessment of bone for the presence of osteoporosis
and/or cortical fractures.
• identification of joint effusions.
• evaluation of soft tissue masses.
• investigation of foreign bodies.
• investigation of vascular disease.
• sports injuries.
• palpable or suspected periarticular or intra-articular
masses , rheumatologic disorders.
•
to assess complications of surgical procedures.
Equipment
Equipment
Normal US machine is composed of the
following:I. display
II. Keyboard
III. Transducer
IV. CPU
V. Disk storage
VI.Pulse controls
VII.Printer
VIII.Transmitter.
Types of Transducers
• Transducer : is small hand held device resembles a
microphone attached to scanner by cord , TD convert
electrical energy to acoustic energy ,and acoustic
energy to electrical signal (TD used as transmitter and
detector).
• There is many types of transducer, the following are
the most popular types:I. Sector transducer
II. Linear transducer
III. Convex transducer
Cross section through Transducer
US physics
introduction
• The basis of all ultrasound applications are the
detection and display the acoustic energy
reflected from organ.
• Sound waves are transmitted as a series of
alternating pressure waves with high pressure
(compression) and low pressure (rarefaction)
pulses.
• Infrasound waves
• Audible sound waves
• Ultrasound waves
• Ultrasound waves propagating through body
tissues a fluid (longitudinal wave) producing
compression and rarefaction of conducting
medium.
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Wavelength
Frequency
Propagation
Propagation velocity
Technique
How is the procedure performed
for certain ultrasound examinations of the
musculoskeletal system the patient may be
seated on an examination table or a swivel
chair. for other US exams, the patient is
positioned lying face-up or face-down on an
examination table. The radiologist or
sonographer may ask you to move the
extremity being examined or may move it for
you to evaluate the anatomy and abnormality
• Most US studies of infants and children are
performed with the child lying on his or her
back on the examination table, but other
positions may be required.
• After you are positioned on the examination
table, the radiologist or sonographer will apply
a warm water-based gel to the area of the
body being studied.
• The transducer is placed on the body and
moved back and forth over the area of interest
until the desired images are captured.
•Example for some
techniques
The Hand
fracture of the base of the distal
phalanx of the 5th finger
Radiographic image
Ultrasound image
the Elbow joint
Fracture of the proximal radius in a
child.
KNEE JOINT
Patellar Fracture
MSK ultrasound
artifacts
Artifacts in Musculoskeletal U/S
• A distortions or errors that affect in image acquisition
and interpretation .
• Artifact may be related to:_
• US beam characteristics errors ( beam width, anisotropy)
• attenuation errors ( acoustic shadowing and increased
acoustic enhancement)
• may be associated with multiple echoes Reverberation).
• Anisotropy
This artifact is more frequent and pronounced in
echogenicity of the examined soft tissue when the US beam
is not directed perpendicular to the examined anatomical
tendons and ligaments due to their oblique course, and it
can mimic pathology
Fig. 2 Anisotropy of the peroneal
tendons.
Posterior acoustic shadowing
artifact
• Posterior acoustic shadowing is an artifact
that occurs when the US beam is high
reflected, or more attenuation
ultrasound image of the Achilles tendon
shows “clean” shadowing
Reverberation artifact
 occur When examining two parallel highly reflective
surfaces and have two type:1- Comet-tail artifact appears as a dense tapering
trail of echoes This type of artifact occurs when there is
a marked difference in acoustic impedances between
an object and the surrounding tissues
2-Ring down artifact is a posterior reverberation
artifact
seen with scanning metal surfaces and has an
appearance
of a series of more continuous reflective echoes
ultrasound image of the proximal
forearm
the lateral aspect of a knee in a patient with
total knee arthroplasty
Musculoskeletal
ultrasound benefits
,limitations, and risks
Benefits:
• Most US scanning is noninvasive(no needles or
injection).
• Occasionally, an US exam may be temporarily un
comfortable, but it is almost never painful.
• US is widely available, easy to use and less
expensive than other imaging modalities.
• US imaging extremely safe and dose not use any
ionizing radiation.
• US scanning gives a clear picture of soft tissue
that do not show up well on x-ray images.
• US provide real-time imaging, making it a good
too for guiding minimally invasive procedures
such as needle biopsies and fluid aspiration.
• Patients with cardiac pacemakers and certain types of
metallic implants or fragments in the body cannot be
safely exposed to strong magnetic field required for
MRI, however patients can safely receive US imaging.
• Because US images are captured in real time they can
show the movement of soft tissue structures such as a
tendon, joints or an extremity.
• US imaging is faster than MRI and dose not required the
patient to remain completely still, allowing infants to be
imaged without sedition.
• The hip joint of infants, un like those of adults, are
largely made of cartilage.US is able to clearly see
cartilage .
Limitations:
• US has difficulty penetrating bone and therefore
can only see the outer surface of bony structures
and not what lies within (infant) who have more
cartilage.
• There are also limitation to the depth that sound
waves can penetrate , there for deeper structure
in larger patients may not be seen .
• It depends on personal skills.
Risks:
• FOR STANDERD DIAGNOSTIC US THERE ARE
NO HARMFUL EFFECTS ON HUMANS
Presented by
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References:
Understanding Bone responses in B-mode Ultrasound Images and Automatic Bone Surface
extraction using a Bayesian Probabilistic Framework
Ameet Kumar Jain, Russell H. Taylor Computer Integrated Surgical Systems and Technology,
Department of Computer Science, Johns Hopkins University, Baltimore, MD - 21218
The registration of preoperative CT to intra-operative reality systems is a crucial step in Computer
Assisted Orthopedic Surgery (CAOS). The intra-operative sensors include 3D digitizers, fiducials, Xrays and Ultrasound (US). Although US has many advantages over others, tracked US for Orthopedic
Surgery has been researched by only a few authors. An important factor limiting the accuracy of
tracked US to CT registration (1-3mm) has been the difficulty in determining the exact location of the
bone surfaces in the US images (the response could range from 2- 4mm). Thus it is crucial to localize
the bone surface accurately from these images. Moreover conventional US imaging systems are
known to have certain inherent inaccuracies, mainly due to the fact that the imaging model is
assumed planar. This creates the need to develop a bone segmentation framework that can couple
information from various post-processed spatially separated US images (of the bone) to enhance the
localization of the bone surface.
In this paper we discuss the various reasons that cause inherent uncertainties in the bone surface
localization (in B- mode US images) and suggest methods to account for these. We also develop a
method for automatic bone surface detection. To do so, we account objectively for the high-level
understanding of the various bone surface features visible in typical US images. A combination of
these features would finally decide the surface position. We use a Bayesian probabilistic framework,
which strikes a fair balance between high level understanding from features in an image and the low
level number crunching of standard image processing techniques. It also provides us with a
mathematical approach that facilitates combining multiple images to augment the bone surface