Dutton Chapter31 Imaging Studies
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Transcript of Dutton Chapter31 Imaging Studies
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Chapter 31
Imaging Studies in Orthopaedics
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Overview
The availability of diagnostic images to
physical therapists greatly depends on
the practice setting. Outside of the United States military
health system, the ordering of imaging
studies is not within the scope ofphysical therapy practice
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Imaging Studies
The results from imaging studiesshould be used in conjunction with
other clinical findings In general, imaging tests have a high
sensitivity (few false negatives), but
low specificity (high false-positive rate)
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Radiology
The following structures are in order ofdescending density: Metal
Bone. Bone can have varying densities withinthe body. For example, cancellous bone is lessdense than cortical bone, and will thus appearlighter than the cortical bone
Soft tissue
Water or body fluid
Fat
Air. As air is the least dense material in thebody, it absorbs the least amount of x-ray
particles, resulting in the darkest portion of thefilm
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Radiology
Plain-film, or conventional, radiographsare relatively inexpensive and give an
excellent view of cortical bone May be more specific than MRI in
differentiating potential causes of bonylesions
Not considered sensitive to the earlychanges associated with tumors,infections, and some fractures
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Radiology
When evaluating radiographs, a
systematic approach such as the
mnemonic ABCS is recommended;A = Architecture or alignment
B = Bone density
C = Cartilage spaces
S = Soft tissue evaluation
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Radiology
A stress radiograph is a procedureusing radiographs taken while stress is
applied to a joint Can be helpful in assessing spinal
stability
Video fluoroscopy procedures involvethe use of x-rays to evaluate the
quality and quantity of joint motion
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Radiology
Contrast-enhanced radiography
procedures involve the use of a
contrasting agent to highlight differentstructures. Examples include:
Arthrography
Angiography
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Computed Tomography
(CT)Also known as computerized axial
tomography (CAT) and computerized
transaxial tomography (CTI). Uses a fan-like beam of x-rays to provide
an almost three-dimensional ortomographic image
Helpful in the examination of acutefractures, aneurysms, infections,hematomas, cysts and tumors
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Computed Tomography
(CT) Image quality in CT imaging depends on a
variety of factors which are mostly selected
by the operator. Two parameters are usedto define the image quality of a given
system:
Spatial resolution: the ability of the system to
distinguish between two closely spaced objects. Contrast resolution: the ability of the system to
discriminate between two adjacent areas with
different attenuation values
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Computed Tomography
(CT) CT scan provides good visualization of
the shape, symmetry, and position of
structures by delineating specific areas This information can be helpful in the
examination of acute trauma, aneurysms,
infections, hematomas, cysts, and tumors
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Magnetic Resonance
Imaging (MRI)
MRI images are the result of the
interaction of body tissues withelectromagnetic forces
Commonly used to assess the central
nervous system, and soft tissueinjuries
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Magnetic Resonance
Imaging (MRI) The advantages of MRI include its
excellent tissue contrast, ability to
provide cross-sectional images,noninvasive nature, and complete lack
of ionizing radiation. MRI provides an
excellent view of anatomic andphysiologic tissues
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Radionuclide Scanning
Involve the diagnostic use of
radioactive material or isotopes thatare administered orally orintravenously
This test is used to detect particularareas of abnormal metabolic activitywithin a bone