Diagnostic Imaging Flashcards
Why is diagnostic imaging lower on an evaluation algorithm?
- it could bias the evaluation process
- should support the evaluation, not form it
- it is considered as a special test
How many views should you get when ordering diagnostic imaging?
At least two
What views should you get for the lumbar spine?
anterior-posterior and lateral (not oblique)
Should you get AP or PA views when imaging for scoliosis? Why?
PA… there is a 3-7x reduction in lifetime ionizing radiation
definition: film comes out as black/grey due to the lack of absorption of ionizing radiation in LESS dense materials
radiolucent
definition: film comes out as white due to the absorption of ionizing radiation in MORE dense material
radiopaque
definition: when the bone becomes more dense due to calcium deposition to the area causing the bone to become thicker/stronger
osteoblastic activity
definition: when there is a depletion of calcium making the bone weaker/thinner
osteoclastic activity
What type of radiograph activity is radiopaque (whiter) indicating an increased radiodensity? Osteoblastic or osteoclastic?
osteoblastic
What type of radiograph activity is radiolucent (darker) indicating a decreased radiodensity? Osteoblastic or osteoclastic?
osteoclastic
What has the highest radiodensity?
heavy metals
What has the lowest radiodensity?
air
What does the acronym ABCs stand for?
Alignment
Bone density
Cartilage spaces
Soft tissues
What is important about spaces between the bones?
it can give information on how healthy the surrounding soft tissue is
–> decreased space can be indicative of OA
(true/false) When looking at radiographs, you should look at the most obvious things first.
False
What can you see on a radiograph that can be an indication of a fracture?
lightening bolts in the periosteum and cortex
What could a twisting line on a bone be instead of a fracture?
it could be a nutrient artery going into the bone
What are looked for when inspecting the alignment of the spinal column?
Spinal lines
What are the spinal lines?
anterior spinal line
posterior spinal line
spinolaminal line
spinous process line
When looking at a tag in a radiograph, if the ball-bearings are in the middle, what position was the photo taken in?
NWB
A Hangman’s fracture is a fracture in the ____ vertebrae.
C2
A clay shoveler’s fracture is a fracture in the ____ vertebrae.
C6/C7
Describe a Grade I fracture.
Fracture is only through the physis
Describe a Grade II fracture.
fracture is through the physis and metaphysis
Describe a Grade III fracture.
fracture is through the physis and epiphysis
Describe a Grade IV fracture.
fracture is through the physis, metaphysis, and epiphysis
Describe a Grade V fracture.
crush/pressure injury to the physis
What are characteristics of a vertebrae that has arthritis?
Bumps/bone spurs/beaking
Rough surface
Vertebral bodies begin to look like an hourglass
Can start in mid-20s
definition: imaging that uses radio frequency impulses in a magnetic field with a small amount of radiation
MRI
MRI works by alignment of nuclei with an odd # of protrons/neutrons (parallel/perpendicular) to the magnetic field
parallel
What are T1 weighted images?
fattier contents become white
What are T2 weighted images?
Water contents become white
What type of weighted MRI best demonstrates anatomic structure?
T1
What type of weighted MRI is most helpful in contrasting normal and abnormal tissue?
T2
Water, CSF, acute hemorrhage, and soft tissue tumors appear (dark/bright) on a T1 MRI and (dark/bright) on a T2 MRI.
dark, bright
What type of radiography is the most sensitive method for detection of early osteonecrosis?
MRI
What type of radiography is the most sensitive method for detection PCL?
MRI
What type of radiography is the most sensitive method for detection of occult fractures?
MRI
What percent of subjects > 40 y/o have an abnormality found in their c-spine on an MRI?
28%
What percent of subjects < 40 y/o show evidence of lumbar disc herniation with MRI imagining?
20-30%
What percent of subjects > 60 y/o show evidence of degeneration and bulging of one or more lumbar disc on an MRI?
93%
What percent of patients cannot tolerate MRI machines due to claustrophobia?
10%
What diagnostic imaging is great for identifying spinal lesions?
CT
What diagnostic imaging demonstrates bony abnormalities better than any other study?
CT
What diagnostic imaging is valuable for evaluating the following:
- C1/C2 subluxation
- subtalar joint and coalitions
CT
definition: Uses marker (Technetium-99m phosphate) to reflect increased blood flow & metabolism/metabolic uptake
bone scans (nuclear medicine tests)
What diagnostic is very useful in diagnosis of subtle fractures, avascular necrosis, decreased bloodflow, osteomyelitis, THA/TKA loosening?
bone scan (nuclear medicine tests)
What ultrasound transducer is a mid-range transducer?
linear
What ultrasound transducer is used for deeper structures (hip joint, fetus, etc)?
curved linear
What ultrasound transducer is used when looking at very superficial structures?
compact linear (hockey stick)
What is the single most over-requested diagnostic imaging procedure?
lumbar radiography
What is not recommended for acute LBP (<1 month)?
lab tests
radiographs
advanced imaging
What are exceptions to order special tests for acute LBP (<1 month)?
age > 50
history of primary cancer
unexplained weight loss
progressive neurological deficit
severe radicular pain
suspicion for Fx or infection
patient request
What is the indication for an oblique projection view of the lumbar spine?
suspicion of a fracture in the pars interarticularis
What is it called when a lumbar vertebrae has no anterior migration but the pars interarticularis is fractured?
spondylolysis
What is the weakest portion of a vertebrae?
pars interarticularis
(true/false) MRI is probably not medically necessary in adult patient with low back pain without neurological deficits AND without signs of serious disease or “red flags” unless surgery is being considered.
true
