Medical Imaging Part 1 Flashcards
(117 cards)
1
Q
Q: What is the error rate in radiological interpretation (by radiologists and radiology residents)?
A
May be as high as 20-40%
2
Q
Defn: Errors of observation
A
The image doesn’t look like what you think it is Ex. Fracture doesn’t show up
3
Q
Defn: Errors of interpretation
A
The injury is there but the radiologist misses it. Ex. Fracture is there but is not seen
4
Q
T/F: With interpretation, insignificant findings may prove significant, while significant findings may prove insignificant.
A
True
5
Q
Q: What can a PT offer when interpretation is difficult for even the specialist? (3)
A
- Managing care 2. Directing imaging 3. Relating imaging studies to clinical evaluation
6
Q
T/F: PT’s should be independently interpreting imaging results.
A
False
7
Q
T/F: Diagnostics are the tools and are the answer.
A
False: they are a tool, NOT the answer.
8
Q
T/F: Diagnostic findings, including imaging, must be used in the context of clinical presentation.
A
True
9
Q
T/F: Diagnostic imaging and PT improves the PT/physician communication.
A
True
10
Q
T/F: Diagnostic imaging and PT adds nothing to the comprehensive PT eval.
A
False: enhances
11
Q
T/F: diagnostic imaging and PT guides and informs the PT’s treatment plan.
A
True
12
Q
Q: By what percent was diagnostic imaging reduced when military PT’s were given the ability to order images.
A
50%
13
Q
Defn: True positive
A
Test detects something that is really there
14
Q
Defn: False positive
A
Test detects something that is not really there
15
Q
Defn: True negative
A
Test detects nothing and nothing is there
16
Q
Defn: False negative
A
Test detects nothing, but there is something there
17
Q
Term: Refers to a test’s ability to identify a true positive.
A
Sensitivity
18
Q
Defn: Sensitivity
A
A test’s ability to identify a true positive
19
Q
Q: Sensitivity - A negative test means…
A
You definitely don’t have the condition
20
Q
Q: What acronym is helpful for sensitivity?
A
SNOUT Sensitivity, Negative, Ruled Out
21
Q
Term: Refers to a test’s ability to identify a true negative
A
Specificity
22
Q
Defn: Specificity
A
A test’s ability to identify a true negative
23
Q
Q: Specificity - A positive test means…
A
You definitely have a condition
24
Q
Q: What acronym is helpful for specificity?
A
SPIN Specificity, Positive, Ruled In
25
Q: Given that HIV blood tests are very sensitive, what can you assume about the presence of the virus from a negative test?
That the test will rarely come up negative is the virus is present - SNOUT
26
Q: Given that home pregnancy tests are very specific, what can you assume about the presence of a pregnancy from a positive test?
That a positive test is almost always due to pregnancy - SPIN
27
Q: What are the 4 advantages of conventional radiographs (x-rays)?
1. Time and cost efficient
2. Non-invasive
3. Low risk
4. Good for screening
28
Q: What is the first order diagnostic modality?
Conventional radiographs or x-rays
29
Q: What is the main disadvantage of conventional radiographs?
They may be normal when a pathology actually exists
30
Diagram: X-ray Basics
31
Term: Reduced strength or density of the x-ray beam as it passes through a medium
Attenuation
32
Term: Ability of the x-ray beam to pass through substance to reach the film plate
Permeability
33
Q: What color is the exposed film in radiographic images?
Dark
34
Term: X-ray absorption capacity, based on substances composition, density, and thickness
Radiodenisty
35
T/F: The radiodensity of an object is directly related to the radiodensity (amount of blackening) on the radiograph.
False: inversely
36
Q: High object radiodensity results in _____________ radiography density on the film, thus the object appears \_\_\_\_\_\_\_\_.
Decreases, whiter
37
T/F: A radiograph is simply a representation of the radiographic densities of anatomical structures
True
38
Term: easily penetrated by x-rays - i.e. low attenuation
Radiolucent substance
39
Term: Not easily penetrated by x-rays - i.e. high attenuation
Radioopaque substance
40
Q: List the substance that represents the color on radiograph (shown below) from darkest to lightest.
1. Air
2. Fat
3. Water
4. Bone
5. Contrast Media
6. Heavy Metals
41
Diagram: Radiograph coloring review
42
Table: Fill in the table below
43
Q: What is the least radiodense stubstance in the body?
Air
44
Q: What contrast media is typically used?
Barium sulfate (in swallow studies)
45
T/F: In x-rays, one view is no view.
True, in terms of interpretation. X-rays are 2D images, need more than one image to reconstruct into 3D
46
Term: visibility of the image
Photographic qualities
47
Term: amount of blackening on the radiograph dependent on distance, time, and current
Density
48
Term: differences between adjacent tissue densities
Contrast
49
Term: Clarity of the image
Geometric qualities
50
Term: also known as sharpness or resolution
Detail
51
Term: Maximized by positioning patient so structure of interest is closest to film plate
Detail
52
Term: Usually occurs due to distance between beam source, patient, and image receptor, and from alignment and positioning issues
Distortion
53
Q: What gives an x-ray image with the most detail and least distortion?
Have the part of interest as close to the film or plate as possible
54
Term: Image appears shorter and wider than the actual object or structure
Foreshortening
55
Term: Objects or structures further from the film appear larger than closer points
Magnification
56
Q: How are radiographs named?
For the beam directions relative to the patient/patient position
57
Q: What are the 3 common radiograph names?
anterioposterior (AP), posterioanterior (PA), Lateral/oblique
58
Q: How are lateral view named?
For the side closer to the film plate
59
Q: What is one thing to be careful of when viewing radiographs?
The identification letters may appear backward or upside down
60
Q: What are the ABCs of Radiology?
Alignment, Bone Density, Cartilage, Soft tissue
61
Content: The 4 parts of alignment
1. Gross bone size
2. Number of bones
3. Shape and contour of cortical outline
4. Joint position and alignment
62
Diagram: In the image below label each line
Red = anterior vertebral line
Blue = posterior vertebral line
Green = spino-laminar line
Orange = posterior spinous line
63
Content: 4 parts of bone density
1. Cortical margins dense, lower density in cavity
2. Weight bearing should be higher density
3. Osteoporosis is suggested by low contrast - "washed out"
4. Sclerosis or arthritis will appear as a brighter white
64
Diagram: Identify the problem
Biconcave "fish" vertebrae, indicative of osteopenia
65
Diagram: Identify the problem
Metastic bone lesion (from primary lung cancer)
66
Content: 4 parts of cartilage
1. Joint space width
2. Subchondral bone
3. Joint margins (smoothness)
4. Epiphyses and growth plates
67
Diagram: Identify the problem
Osteoarthritis of the left hip, with joint collapse
68
Content: 3 parts of soft tissue
1. Gross size of musculature
2. Outline of joint capsules
3. Periosteum
69
Diagram: Identify the problem
Fat pad or "sail" sign: note faint density change at arrows as edema pushes fat pad out of fossa
70
Diagram: Identify the problem
Left intertrochanteric and subtrochanteric hip fractures
71
Diagram: Identify the problem
"Teardrop" fracture of 2nd cervical vertebrae
72
Diagram: Identify the problem
Osteonecrosis of femoral head, femoral head begins to flatten
73
Diagram: Identify the problem
Compression fracture of 4th lumbar vertebrae
74
Defn: Contrast enhancement
Injection or ingestion of radiocontrast medium prior to radiographic study
75
Diagram: Identify the contrast enhancement
Barium swallow
76
Content: Computed tomography basics (4)
1. Uses x-ray attenuation to produce cross-sectional images
2. X-ray tube and film move about a fulcrum
3. Provides detailed anatomical imaging of bone
4. Travserve images are read from the bottom looking up
77
Diagram: CT Basics
78
Q: What are the 2 advantages of CT?
1. Sensitive and specific for fracture
2. Useful for rapid assessment of brain or neurologic injury
79
Q: What are the 3 disadvantages of CT?
1. Radiation exposure
2. Discriminates density, but limited in precise histologic differences
3. Small volume of tissue image as a uniform shade of gray
80
Diagram: Identify the image below
CT image of left actabular fracture
81
Diagram: Identify the image below
3D image of tibial plateau and proximal fibular fractures
82
Q: How does an MRI generate an electromagnetic field?
Uses pulses of radiofrequnecy and a strong external magnet
83
Term: Atomic nuclei allign in an electromagnetic field
Resonance
84
Q: During an MRI, nuclei realign to their _________ state when the field is \_\_\_\_\_\_\_\_\_, release _________ energy.
Resting, removed, resonant
85
Q: What produces a radio frequency signal that can be captured and processed into an MRI image?
The release of resonant energy
86
Content: 4 advantages of MRI
1. Good sensitivity
2. Images soft tissue well
3. No radiation
4. Little distortion as images are obtained in one plane
87
Content: 3 disadvatnages of MRI
1. Relatively low specificity
2. Expensive
3. Contraindicated if pt. has ferrous metal implant or exposure
88
T/F: Ortopedic hardware is ferromagnetic, however surgical clips and pacemakers are safe during an MRI.
False, flip it
89
T/F: MRI images are based on two different processes of proton realignment.
True
90
Term: How long it takes protons to relax back to resting state following a RF pulse
Longitudinal magnetization (T1)
91
Term: How long resonating protons remain in phase following a RF pulse
Transverse magnetization (T2)
92
Table: Fill in the table below
93
Q: With ________ MRI, tissue enhancement is ______________ to blood flow to the tissue.
Contrast, proportional
94
Q: In what ways can MRI contrast be delivered into the pt.'s system?
IV or intra-joint injection
95
Diagram: Identify the type of MRI image.
T2 image of a herniated lumbar disk
96
Diagram: Identify the type of MRI image
T1 image of right hip chondrosarcoma
97
Diagram: Idenifty the type of MRI image
T2 image of tibial plateau and femoral condyle contusion
98
Content: Functional MRI (2)
1. Based on increased BF that accompanies cerebral activity
2. Uses magnetic properties of deoxyhemoglobin as an endogenous contrast agent
99
Content: DEXA (4)
1. Gold standard for body composition
2. Measure bone density
3. Determines density based on difference between absorption of beams
4. Radiation exposure approx. = to a flight from NYC to LA and back
100
Content: Nuclear Medicine (3)
1. Uses radiopharmaceuticals for diagnosis, therapy, and reserach
2. Radiopharmaceuticals are radioactive tracers that are absorbed according to the metabolic properties of the tissue
3. Detection of the location and concentration of radioactive elements is used to produce an image
101
Content: Types of Nuclear Medicine (4)
1. SPECT
2. PET
3. SPECT or PET in combo with CT
4. Radionuclide scintigraphy or bone scan
102
Content: Radionulcide scintigraphy (3)
1. Labeled methylene is injected, scanning occurs 2-3 hours following injection
2. High uptake = increased bone activity or mineral turnover
3. Modality of choice for detecting stress fractures and metastatic bone disease
103
Content: 3 advatanges of radionuclide scintigraphy
1. Highly sensitive for early bone and joint disease
2. Fast
3. Reasonable cost
104
Content: 2 disadvantages of radionuclide scintigraphy
1. Poor specificity
2. Easily influenced by osteoblastic activity or BF of any etiology
105
Diagram: Idenifty the type of image
Radionuclide scintigraphy - metastatic prostate cancer
106
Content: Ultrasonography (4)
1. Images produced by sound waves
2. Tissues have unique acoustic qualities
3. Useful for OBGYN and musculoskeletal tissue
4. Can be used with activity
107
T/F: Ultrasound is operator independent, and does not require practice to have good technique.
False
108
T/F: Ultrasound is included in the PT practice act, but should only be used to confirm diagnosis.
True
109
Q: ____________ \_\_\_\_\_\_\_\_\_\_\_\_ are generally the first order modality.
Conventional , radiographs
110
Q: ______ is used to visualize complex anatomy
CT
111
Q: ________ is used to assess soft tissue.
MRI
112
Content: 3 parts of a trauma survey
1. Diagnose and evaluate fracture or disloaction
2. Match MOI to clinical presentation
3. Assess treatment and monitory healing
113
Q: What types of images are typically taken for a trauma evaluation? (3)
1. Lateral chest
2. AP chest
3. AP pelvis
114
Diagram: Identify the following clinical decision rule;
Sensitivity \_\_\_\_\_\_, Specificity \_\_\_\_\_\_
Pittsburg Decision Rule for Knee Trauma
99%, 60%
115
Diagram: Identify the following clinical decision rule;
Sensitivity \_\_\_\_\_\_, Specificity \_\_\_\_\_\_
Ottowa Knee Rule
97%, 27%
116
Diagram: Identify the following clinical decision rule;
Sensitivity \_\_\_\_\_\_, Specificity \_\_\_\_\_\_
Ottowa Ankle and Foot Rules
100%, 40%
117
Diagram: Identify the following clinical decision rule;
Imaging Guidelines for Actue LBP
