Medical Imaging Part 1 Flashcards Preview

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Flashcards in Medical Imaging Part 1 Deck (117):
1

Q: What is the error rate in radiological interpretation (by radiologists and radiology residents)?

May be as high as 20-40%

2

Defn: Errors of observation

The image doesn't look like what you think it is Ex. Fracture doesn't show up

3

Defn: Errors of interpretation

The injury is there but the radiologist misses it. Ex. Fracture is there but is not seen

4

T/F: With interpretation, insignificant findings may prove significant, while significant findings may prove insignificant.

True

5

Q: What can a PT offer when interpretation is difficult for even the specialist? (3)

1. Managing care 2. Directing imaging 3. Relating imaging studies to clinical evaluation

6

T/F: PT's should be independently interpreting imaging results.

False

7

T/F: Diagnostics are the tools and are the answer.

False: they are a tool, NOT the answer.

8

T/F: Diagnostic findings, including imaging, must be used in the context of clinical presentation.

True

9

T/F: Diagnostic imaging and PT improves the PT/physician communication.

True

10

T/F: Diagnostic imaging and PT adds nothing to the comprehensive PT eval.

False: enhances

11

T/F: diagnostic imaging and PT guides and informs the PT's treatment plan.

True

12

Q: By what percent was diagnostic imaging reduced when military PT's were given the ability to order images.

50%

13

Defn: True positive

Test detects something that is really there

14

Defn: False positive

Test detects something that is not really there

15

Defn: True negative

Test detects nothing and nothing is there

16

Defn: False negative

Test detects nothing, but there is something there

17

Term: Refers to a test's ability to identify a true positive.

Sensitivity

18

Defn: Sensitivity

A test's ability to identify a true positive

19

Q: Sensitivity - A negative test means...

You definitely don't have the condition

20

Q: What acronym is helpful for sensitivity?

SNOUT Sensitivity, Negative, Ruled Out

21

Term: Refers to a test's ability to identify a true negative

Specificity

22

Defn: Specificity

A test's ability to identify a true negative

23

Q: Specificity - A positive test means...

You definitely have a condition

24

Q: What acronym is helpful for specificity?

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

A image thumb
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.

Q image thumb

1. Air

2. Fat

3. Water

4. Bone

5. Contrast Media

6. Heavy Metals

41

Diagram: Radiograph coloring review

A image thumb
42

Table: Fill in the table below 

Q image thumb

A image thumb
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 

Q image thumb

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

Q image thumb

Biconcave "fish" vertebrae, indicative of osteopenia

65

Diagram: Identify the problem 

Q image thumb

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

Q image thumb

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 

Q image thumb

Fat pad or "sail" sign: note faint density change at arrows as edema pushes fat pad out of fossa

70

Diagram: Identify the problem 

Q image thumb

Left intertrochanteric and subtrochanteric hip fractures

71

Diagram: Identify the problem 

Q image thumb

"Teardrop" fracture of 2nd cervical vertebrae

72

Diagram: Identify the problem 

Q image thumb

Osteonecrosis of femoral head, femoral head begins to flatten 

73

Diagram: Identify the problem 

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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

Q image thumb

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

A image thumb
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 

Q image thumb

CT image of left actabular fracture

81

Diagram: Identify the image below 

Q image thumb

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

Q image thumb

A image thumb
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.

Q image thumb

T2 image of a herniated lumbar disk

96

Diagram: Identify the type of MRI image

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T1 image of right hip chondrosarcoma 

97

Diagram: Idenifty the type of MRI image

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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

Q image thumb

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 ______

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Pittsburg Decision Rule for Knee Trauma

99%, 60%

115

Diagram: Identify the following clinical decision rule; 

Sensitivity ______, Specificity ______

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Ottowa Knee Rule

97%, 27%

116

Diagram: Identify the following clinical decision rule; 

Sensitivity ______, Specificity ______

Q image thumb

Ottowa Ankle and Foot Rules

100%, 40%

117

Diagram: Identify the following clinical decision rule; 

 

Q image thumb

Imaging Guidelines for Actue LBP