Radiology Flashcards
When is CT head w/ contrast good?
to evaluate for AV malformations, primary/metastatic tumors
When is a noncontrast head CT good?
to r/o hemorrhage (e.g. trauma, acute neurologic change)
When is abdominal/pelvic CT good?
for retroperitoneal structures (e.g. pancreatitis, pancreatic masses, nodal mets from colon, prostate, testicular, renal malignancies)
When is high-res CT scan of chest used?
parenchymal lung disease (e.g. interstitial fibrosis), bony structures
When is MRI used?
- demyelinating diseases (e.g. MS, some dementias)
- eval of posterior fossa, base of skull, orbit
- eval for acoustic neuromas, pituitary tumors, small intraparenchymal brain tumors
- bone tumors, bone/soft tissue infections (e.g. osteo), joint spaces, aseptic necrosis of femoral head
- disease of spinal cord, spinal column
What should NOT be ordered in patients with renal disease (creatinine >1.5)?
CT w/ contrast, MRI (risk of nephrogenic systemic fibrosis)
What med should be D/Cd before CT w/ contrast?
Metformin (and do not resume until 48 hrs after scan, when renal failure has been r/o’d)
What imaging test is NOT useful in patients with multiple myeloma?
Bone scan (MM has purely lytic metastatic lesions)
When is a HIDA scan the best test?
- evaluating biliary obstruction vs. acute cholecystitis, eval of biliary leaks postop
- congenital abnormalities of biliary tract (incl biliary atresia)
NOT FOR GALLBLADDER STONES
When is bone scan ordered?
- metastatic bone lesions (prostate, breast, kidney, thyroid, lung)
- delayed fractures
- osteomyelitis
- avascular necrosis of femoral head
When is adrenal scan ordered?
To localize pheochromocytoma when MRI/CT nondiagnostic
When is a gallium scan ordered?
test of choice for localizing abscesses, staging lymphomas, melanomas
When is ultrasound the best test?
- eval gallbladder for stones
- assess uterus, adnexa, ovaries (w/ exception of cervical ca)
- eval prostate, obtain biopsy
- eval for DVT
When you see lytic bone lesions on X-ray, think of…
MM, primary bone tumor, met (most common are lung, renal, thyroid, breast)
When you see blastic bone lesions on X-ray, think of…
met (most common breast, prostate, lymphoma), Paget’s disease, medulloblastoma in pedatrics
