BCSE Diagnostic Imaging Interpretation 5 — Questions and Answers
Question 1: On a nuclear medicine bone scan, which pattern is most characteristic of metastatic prostate cancer?
- Multiple asymmetric areas of increased uptake (hot spots) in the axial skeleton (Correct answer)
- A single hot spot in the long bone diaphysis
- Diffusely decreased uptake throughout the skeleton
- Increased uptake symmetrically at all joint spaces
Correct answer: Multiple asymmetric areas of increased uptake (hot spots) in the axial skeleton
Prostate cancer metastases are typically osteoblastic, producing multiple asymmetric hot spots predominantly in the axial skeleton on bone scintigraphy.
Question 2: On CT of the chest, which finding is most suggestive of a malignant solitary pulmonary nodule rather than a benign granuloma?
- Spiculated margins with a diameter >8 mm and no central calcification (Correct answer)
- Dense central or 'popcorn' calcification
- Smooth margins with a small diameter <6 mm
- Laminated calcification throughout the nodule
Correct answer: Spiculated margins with a diameter >8 mm and no central calcification
Spiculated margins, size >8 mm, and absence of benign calcification patterns are the highest-risk CT features for malignancy in a pulmonary nodule.
Question 3: On CT of the abdomen, which finding best describes aortic dissection versus aortic aneurysm?
- An intimal flap creating true and false lumens within the aorta (Correct answer)
- Focal saccular dilation >3 cm beyond normal aortic diameter
- Periaortic stranding without luminal abnormality
- Mural thrombus within a dilated aortic segment
Correct answer: An intimal flap creating true and false lumens within the aorta
Aortic dissection is defined by an intimal flap dividing the aorta into true and false lumens, distinguishing it from aneurysmal dilation.
Question 4: On MRI of the brain, periventricular white matter T2/FLAIR hyperintensities perpendicular to the corpus callosum ('Dawson's fingers') are characteristic of which condition?
- Multiple sclerosis (Correct answer)
- Hypertensive small vessel disease
- Progressive multifocal leukoencephalopathy
- Watershed infarcts
Correct answer: Multiple sclerosis
Dawson's fingers are ovoid MS plaques oriented along perivenular drainage pathways perpendicular to the ventricles, a hallmark of MS on MRI.
Question 5: On plain radiograph, which finding is most consistent with osteosarcoma in an adolescent patient?
- Aggressive periosteal reaction with Codman's triangle and a soft-tissue mass (Correct answer)
- Expansile lytic lesion with a soap-bubble appearance
- Dense ivory vertebra
- Onion-skin periosteal reaction in the diaphysis
Correct answer: Aggressive periosteal reaction with Codman's triangle and a soft-tissue mass
Osteosarcoma classically shows Codman's triangle (elevated periosteum at tumor margin) and sunburst periosteal reaction with an associated soft-tissue mass.
Question 6: On fluoroscopic cystourethrogram (VCUG), which finding is diagnostic of vesicoureteral reflux?
- Retrograde filling of contrast from the bladder into the ureter and renal pelvis (Correct answer)
- Filling defect in the bladder lumen
- Trabeculae of the bladder wall during filling
- Bladder neck narrowing during voiding
Correct answer: Retrograde filling of contrast from the bladder into the ureter and renal pelvis
VUR is diagnosed when contrast instilled into the bladder refluxes retrograde up the ureter and into the renal collecting system.
Question 7: On CT or MRI, a 'target sign' (concentric rings) within a bowel mass is most associated with which diagnosis?
- Intussusception (Correct answer)
- Crohn's disease stricture
- Colon carcinoma
- Ischemic colitis
Correct answer: Intussusception
Intussusception produces a target or bull's-eye sign on cross-sectional imaging, reflecting the telescoped bowel-within-bowel configuration.
BCSE Diagnostic Imaging Interpretation 5
On a nuclear medicine bone scan, which pattern is most characteristic of metastatic prostate cancer?