Imaging I Flashcards
1
Q
Why do we study imaging as a PT?
A
Adds to exam and eval, assists with intervention, contributes to prognosis, and allows better communication of involved parties
2
Q
What are some examples of interventions through imaging?
A
- motion barriers - bone spur
- weight bearing/ functional levels - bony callus
- Location - Bone stimulator
3
Q
What is the first imaging typically performed?
A
radiograph
4
Q
What is a major advantage of a radiograph?
A
Most efficient for INITIAL assessment bone or joint abnormality
5
Q
What is a major disadvantage of a radiograph?
A
limited for complex and subtle bony abnormalities
6
Q
What are radiographs commonly referred to as?
A
Plain films, films, or x-rays
7
Q
What is needed to view all three dimensions with a radiograph?
A
at least 2 images at 90˚
8
Q
One view is ….
A
NO view
9
Q
Why is there standardization of positions and views with a radiograph?
A
- greatest visualization
- minimize radiation exposure
- projection of x-ray beams
10
Q
What are the 3 ways we can project x-ray beams most commonly?
A
- Anterior-Posterior > Posterior-Anterior
- Lateral
- Oblique
11
Q
How does a radiograph work?
A
- x ray beam enters body, absorbed by tissues at differing amounts to produce shades of gray
- x- ray beam emerges from patient and onto an interpretation device or image receptor
12
Q
What is the relationship between radiodensity and radiograph?
A
inverse
13
Q
What color is air on a radiograph?
A
Black
14
Q
What color is fat and bone marrow on a radiograph?
A
Black/gray
15
Q
What color is water, muscle, and soft tissues on a radiograph?
A
gray
16
Q
What color is bone on a radiograph?
A
White
17
Q
What color are contrast dyes on a radiograph?
A
Bright white
18
Q
What color is metal on a radiograph?
A
Solid white
19
Q
How do we view a AP and PA projection radiograph?
A
- place on viewer as if patient were facing you and in anatomical position
20
Q
What is the exception to how we typically view AP and PA projection radiographs?
A
- hands and feet viewed with toes or fingers pointing up
21
Q
How do we a view a lateral radiograph?
A
In the path of a beam
22
Q
What can help up when viewing a radiograph?
A
Identify at least 2 markers
- protected health info
- side of body with a R/L
23
Q
What should we NOT do with the side of body markers on a radiograph?
A
Do NOT orient the slide marker to obtain the correct letter position
24
Q
What are the ABCS of understanding a radiograph?
A
Alignment
Bone density
Cartilage Space
Soft tissue
25
What should we observe about alignment using a radiograph?
- General architecture/anatomy - size, number of bones, etc.
- General contour (spurs, breaks, markings)
26
What is cortical bone in context of imaging?
Outer layer of bone and predominately in appendicular skeleton
- denser and whiter
27
What is cancellous bone in context of imaging?
Interspersed within marrow and predominately in axial skeleton
- less dense and grayer
28
What should we look for concerning bone density on imaging?
Texture/local density such as sclerotic changes (increased bone density - may be abnormal or noramal)
29
What should we look for concerning cartilage spaces?
- narrowing
- subchondral bone sclerosis (body is trying to repair damaged bone) and erosion
- Epiphyseal plates - position, size, and smooth margin
30
What should we look for concerning soft tissue with imaging?
- muscle wasting / edema
- fat pad displacement
- capsular effusion
31
What is periosteum? What will it show up as?
Bone covering that shows up as a soft tissue shadow
32
What does a solid periosteum on imaging indicate?
A slow growth of healing or infection
33
What does a laminated or layered periosteum on imaging indicate?
Repetitive stress
34
What does a spiculated or pointed periosteum indicate on a radiograph?
breakthrough due to tumor
35
What does codman's triangle indicate on a radiograph?
Raised periosteum with any of the mentioned conditions
36
What are some other common MSK imaging mechanisms aside from a radiograph?
- CT (computed tomography)
- MRI ( magnetic resonance imaging)
- Ultrasound (US) imaging
37
What is a CT scan?
Images generated by computerized and targeted x-rays passing through slices of tissue
38
How thick are the slices on a CT?
.1-10 mm thick
39
What are major advantages of a CT scan?
- less overlap of structures due to slicing
- able to locate subtle bone changes
40
What are some major disadvantages of a CT scan?
- greater radiation exposure but getting faster and safer
- limited with soft tissue abnormalities
41
What can be used for more detail on a CT scan?
Contrast agents
42
What is CT the standard modality for? Why?
Standard modality for head and abdominal trauma, in the ER due to shorter scanning times and quick availability
43
Is a CT quicker or slower than MRI and US?
Quicker
44
What do we start with when using a CT (image type)?
Scout image
45
What should we locate with a CT scan?
Specific slice position and image
46
What plane are CT slices in?
Transverse
47
What position is the patient in for a CT?
Supine
48
What should we remember about viewing a CT image?
- patient is supine so anterior surface is at the top of each image
- looking upward at the anatomic structures from below so your right is the patient's left
49
How are sagittal plane slices viewed with a CT scan?
Left to right
50
What is tissue density like? (due to shades)
Like x-ray
51
What is a MRI?
Strong magnetic fields with radiofrequency waves
52
What are the similarities between a MRI and a CT?
- generates thin slices
- may also be used with contrast agents for even more detail
53
What are major advantages of MRI ?
- Less overlap like CT due to slicing
- Excellent at soft tissue abnormailities, cancellous bone / bone marrow conditions; neoplasms and staging metastasis, osteochondral lesions, stress fxs
- no radiation like with CT (high) and x-ray (low)
- high resolution
54
What are the major disadvantages of MRI?
- contraindications with magnetic implants except for stable joint implants
- precaution with claustrophobia
55
How should we orient ourselves to understand a MRI?
- orient to scout image to find slice
- view as with CT
56
What is diagnosis often based on differences between with a MRI?
t1 vs t2 images
57
What should we look for first with a MRI?
Areas of normal fluid first - such as the bladder, synovial joints, cerebrospinal fluid
58
If fluid is bright, likely a ....
T2 image
59
If fluid is dark, likely a ...
T1 image
60
What is a T1 weighted image?
MRI
- bright signals from fat and bone marrow
- dark signals from cortical bone and fluid
61
What is a T1 weighted image best for?
Demonstrating anatomical definition of structure
62
What is a T2 weighted image?
Bright signal occurs from fluid and water
63
What is a T2 weighted image BEST for?
Demonstrating swelling and neoplasms particularly in cancellous bone
64
What structures are often gray in both T1 and T2 images?
Nerve and muscles - have an intermediate signal
65
What is a ultrasound or sonography?
- ultrasound waves are absorbed, reflected, and diffused differently from varying tissues to contruct an image
66
What are major advantages of an ultrasound or sonography?
- Offers real time information for SUPERFICIAL soft tissue
- higher resolution for SUPERFICIAL tendon, ligament, and muscle than MRI
67
What are major disadvantages in an ultrasound or sonography?
- inability to scan deeper joint structures
- image quality highly dependent on operator
68
What does a brighter signal indicate on a US/sonograph?
Swelling, tendinosis (fibrosis/degeneration), aka hyperechoic appearance
69
What do irregular borders or lack of structure indicate with a sonograph/US?
Tears
70
What does a wider structure indicate with a US/sonograph?
Swelling, thickening
71
What is imaging benefitted by?
A thorough hx and exam
72
What are clinical decision rules for imaging?
- following trauma based on supportive clinical findings
- diagnostic and prognostic decisions
- evidence based with research
73
What is the appropriateness criteria?
- foremost decision-making guideline
- guides choice of best imaging tool
- developed by expert radiologists
- may use with or without trauma
74
What are factors for decision making with MSK conditions regarding appropriateness criteria for imaging?
- age: individual risk factors including PMH
- trauma presence/absence
- mechanism of injury
- prior surgery/injury/imaging results
- clinical findings, particularly p! provocation and function such as weight bearing ability
75
If imaging is negative without clinical findings it is...
noramal/asymptomatic
76
What happens when imaging is negative with clinical findings of a condition?
- suspicious condition (i.e. acts like a fx but x-ray negative so consider a more advanced and specific image like a CT)
- NO structural changes and MORE of a biomechanical or overuse etiology
77
What can positive imaging without matching clinical symptoms do for a patient's psychosocial status?
* potential negative effect
- fear of activity
- failure to work
- limit rehab potential
78
What is Imaging BEST AT?
RULING OUT
79
What is normal and abnormal about cortical bone?
Normal: hyper echoic, smooth, continuous
Abnormal: break in continuity, uneven surfaces
80
Which view is the best to pick up stenosis?
Oblique - single side intervertebral foramen
81
what would cause osteophyte formation both anteriorly and posteriorly?
age related disc changes
82
what would cause narrowing of the joint spaces and sclerosis of the articular surfaces at all levels?z
age related JOINT changes
83
what is used for assessment of fractures or dislocations of the PROXIMAL humerus
Scapular Y lateral view
84
What can we use to assess dislocations?
Axillary view
