Master the board step 3

Master the Boards: USMLE Step 3
Bone scan is not useful
in purely lytic metastatic
lesions. It is never the
correct answer in a
patient with multiple
myeloma.
When Are Nuclear Scans the Best Test?
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HIDA (hepatobiliary) scan: This is used for evaluating biliary obstruction
versus acute cholecystitis and the evaluation of biliary leaks postoperatively.
It is also the test of choice to evaluate congenital abnormalities
of the biliary tract, including biliary atresia. It is not the test of choice for
evaluating gallbladder stones.
··
Bone scan: This is used for evaluating metastatic bone lesions (prostate,
breast, kidney, thyroid, lung), evaluating delayed fractures, and evaluating
osteomyelitis and avascular necrosis of the femoral head.
··
Adrenal scan: This is the test of choice to localize pheochromocytoma
when a MRI/CT scan is nondiagnostic.
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V/Q scan: This is the initial test of choice to evaluate for pulmonary embolism
(PE). (A normal study rules out PE. An indeterminate scan requires
further workup with CT angiogram. A perfusion defect with normal ventilation
quite probably indicates PE.) Do not order a V/Q scan in a patient with
COPD or extensive lung disease.
··
Gallium scan: This is the test of choice for localizing abscesses, staging
lymphomas, and melanomas.
When Is Ultrasound the Best Test?
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It is the best initial test to evaluate the gallbladder for stones when a patient
presents with right upper-quadrant pain.
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It is the best initial test for assessing the uterus, adnexa, and ovaries (with
the exception of cervical carcinoma).
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It is the best initial test to evaluate the prostate; it also aids in obtaining
biopsy.
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It is the best test to evaluate for deep venous thrombosis (DVT).
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