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
When you see “large mediastinum,” think of…
AA, lymphadenopathy
When you see lung infiltrated with effusion, think of…
Strep pneumo, lung infarct, TB
When you see SBO, think of…
adhesions, hernia, intussusception (peds), gallstone ileus, carcinoma
When you see large bowel obstruction, think of…
carcinoma, hernia, diverticulitis, intussusception (peds)
When you see gas in biliary system, think of…
gallstone ileus, gas-forming infection, instrumentation
When you see “small kidney(s),” think of…
renal artery disease, chronic hydronephrosis, chronic glomerulonephritis, chronic pyelonephritis
When you see “large kidney(s),” think of…
acute pyelonephritis, acute glomerulonephritis, renal vein thrombosis, carcinoma (unilateral), Wilms’ tumor (peds)
When you see ring-enhancing lesion in brain, think of…
- immunocompetent patients: metastatic tumors, demyelinating disease, pyogenic abscess
- immunocompromised: toxo, primary CNS lymphoma (EBV), TB (endemic areas)
When you see hemorrhage into basal ganglia, cerebellum, or pons, think of…
hypertensive brain hemorrhage
When you see hemorrhage into the cerebral hemispheres, think of…
AV malformation, aneurysm, trauma, metastatic lesions, other (vasculitis, cocaine, coagulation abnormalities)
