Diagnostic Imaging Flashcards
bone should show up as ______ on xray
white
fat would show up as ______ on xray
dark
list 3 advantages of xrays
Easily available + Quick
Inexpensive
Relatively low radiation
Good detail (bone definition)
list 3 disadvantages of xray
May not reveal process until very advanced
2D image = requires multiple views
Less soft tissue detail
4 OA related terms
osteophytes
subchondral sclerosis
subchondral cyst
central erosion
what is osteopenia
loss of bone density
what are bony outgrowth at edge of joint
osteophytes
what are extra dense bones around joint
subchondral sclerosis
what are pockets of synovial fluid in bone near joint
subchondral cysts
what is a break in cortical bone at the center of the joint
central erosion
Joint space narrowing means that
hyaline cartilage thinned
osteopenia means that
Less bone being formed
Bone being lost
May be inflammation in or next to the bone
osteophytes means that the joint is undergoing ________ and is typically associated with __________
degeneration
OA
subchondral sclerosis is seen when there is abnormal _______________, typically associated with _______
mechanical stresses on the bone
OA
subchondral sclerosis looks _____ on xray
white
subchondral cysts are usually associated with
OA
what are subchndral cysts called when large
geodes
central erosion means that there is
Degeneration with inflammation resulting in breaks and erosions at joint surface
Occurs with erosive OA
what is marginal erosion
loss of bone at joint margin
what is juxtaarticular erosion
away from joint margin
what is central erosion
in middle of joint
marginal erosion is common in
RA, PsA
juxtaarticular erosion is common in
gout
pencil in cup is typical of
PsA
fusion is common in
SpA
periostitis is ___________ common in ______
fluffy new bone growth along shaft
SpA
fusion means
Inflammatory process has occurred + healing resulted in fusion
May have been past trauma + bones fused when they healed
periostitis means there is ______ affecting the ________ layer of the bone
inflammation
periosteal
ulna deviation means that there is
Laxity of soft tissue supports at the joints
ulna deviation is often seen in
RA
what is subluxation
bones not aligned at joint
Distribution of affected hand joints more transverse- affects all same joints across hands
RA
Affects each individual digit differently, more subluxation, pencil in cup
psoriatic arthritis
Mostly PIP and DIP affected, bony but not squishy/ swelling
osteoarthritis
scoliosis is
lateral curvature to spine
spondylolisthesis
displacement of 1 vertebrae over another
sacrolitis is
inflammation of SI joints
syndesmophytes is
bony growths along a ligament
how does ultrasound work
Cross sectional imaging that relies on reflection of sound waves off tissue interfaces
ultrasound bright means
hyperechoic- bone
ultrasound dark means
hypoechoic = fluids/ not dense
doppler signal measure
blood flow to area
echogenicity is
relative to surrounding tissues
ultrasound is indicated for
soft tissue pathology
bony pathology
pros of ultrasound
Inexpensive and portable
Can compare both sides of body
Dynamic eval of structures (Stress or stretch)
Can press with transducer to identify source of pain
No ionizing radiation
cons of ultrasound
Operator dependent
Time consuming
U/S waves do not penetrate bone, can not cross air
CT is
Cross sectional imaging technique merging xray technology with computer processing/ reconstruction to see 3D images
CT indications
Good for bone, soft tissue, blood vessel imaging
Gout protocol (dual energy CT gout)
CT pros
Very detailed images
Widely available
Less time consuming than U/S or MRI
Less expensive than MRI
Safe for those with metal devices
CT cons
More radiation
Less soft tissue distinction compared to MRI
Pt must be still
describe how MRI works
cross sectional imaging using a magnetic field and radiofrequency signal to cause hydrogen ions in bodies to emit signals, then convert to image
Principle- different tissues contain different amounts of water (H+) = can visualize the distinction
gadolinium is a
MRI contrast agent
T1 MRI sees fluids as
dark
pros for MRI
good for soft tissues
no ionizing radiaiton
cons for MRI
Expensive
Not as readily available + More time consuming
Not as good for bone
Metal contraindicated + claustrophobia
Must keep still for prolonged period
how do bone scans work
Nuclear medicine imaging - uses radioactive substance to image a physiologic process in body
Radiopharmaceuticals are injected into patient
Ex- MDP (TN-99 = radioactive component)
Affinity for hydroxyapatite crystals (accumulates in areas with increased bone production)
Gamma cameras detect rays emitted by body
bone scan indications
bone metabolism in cancer, emtabolic bone diseases, subtle fractures, osteolyelitis
T or F: bone scan is good for distinguishing types of arthritis
F
bone scan pros
V sensitive
Great for picking up things that shouldn’t be missed
bone scan cons
Pregnancy / breastfeeding
Some radiation emission after scan (t1/2 = 1d)
Structural details not well seen
