BCSE Diagnostic Imaging Interpretation 3 — Questions and Answers
Question 1: On MRI of the knee, a 'bucket-handle' tear of the meniscus is best recognized by which imaging feature?
- A displaced fragment within the intercondylar notch creating a 'double PCL sign' (Correct answer)
- Increased T2 signal at the meniscal root
- Complete absence of the meniscus on coronal imaging
- Vertical cleavage on sagittal T2 imaging
Correct answer: A displaced fragment within the intercondylar notch creating a 'double PCL sign'
A bucket-handle tear displaces the inner fragment into the intercondylar notch, producing a double PCL sign on sagittal MRI.
Question 2: Which CT finding best differentiates a hepatic hemangioma from hepatocellular carcinoma on contrast-enhanced CT?
- Peripheral nodular enhancement in the arterial phase with progressive centripetal fill-in (Correct answer)
- Arterial hyperenhancement with washout in the portal venous phase
- Homogeneous enhancement throughout all phases
- No enhancement in any phase
Correct answer: Peripheral nodular enhancement in the arterial phase with progressive centripetal fill-in
Hemangiomas show peripheral nodular arterial enhancement with progressive fill-in on delayed imaging, while HCC shows arterial enhancement with washout.
Question 3: On a plain radiograph, which feature best distinguishes a pathologic fracture from a stress fracture?
- An underlying lytic or blastic lesion at the fracture site (Correct answer)
- Periosteal reaction along the fracture line
- Location at the femoral neck
- Bilateral symmetric involvement
Correct answer: An underlying lytic or blastic lesion at the fracture site
A pathologic fracture occurs through pre-existing bone disease, so identifying an underlying lesion at the fracture site is the key distinguishing feature.
Question 4: On CT pulmonary angiography (CTPA), which finding is most specific for pulmonary embolism?
- A filling defect within an opacified pulmonary artery (Correct answer)
- Pleural effusion
- Atelectasis
- Consolidation in the lung periphery
Correct answer: A filling defect within an opacified pulmonary artery
A filling defect within a contrast-opacified pulmonary artery on CTPA is the direct and most specific sign of pulmonary embolism.
Question 5: On ultrasound, which finding is most diagnostic of a testicular torsion?
- Absent or markedly decreased Doppler flow in the affected testis (Correct answer)
- Hyperechoic testicular parenchyma
- Increased Doppler flow compared to the contralateral side
- Hydrocele without parenchymal changes
Correct answer: Absent or markedly decreased Doppler flow in the affected testis
Absent or significantly decreased intratesticular Doppler flow confirms testicular torsion and requires emergent surgical intervention.
Question 6: On a barium swallow study, a 'bird-beak' appearance at the gastroesophageal junction is characteristic of which condition?
- Achalasia (Correct answer)
- Esophageal carcinoma
- Zenker's diverticulum
- Diffuse esophageal spasm
Correct answer: Achalasia
Achalasia causes failure of LES relaxation, producing a smooth tapered narrowing at the GEJ resembling a bird's beak on barium swallow.
Question 7: On CT of the chest, a 'crazy paving' pattern (ground-glass opacity with superimposed interlobular septal thickening) is classically associated with which condition?
- Pulmonary alveolar proteinosis (Correct answer)
- Usual interstitial pneumonia
- Sarcoidosis
- Lymphangitic carcinomatosis
Correct answer: Pulmonary alveolar proteinosis
Crazy paving is the classic CT pattern of pulmonary alveolar proteinosis, caused by lipoproteinaceous material filling alveolar spaces.
BCSE Diagnostic Imaging Interpretation 3
On MRI of the knee, a 'bucket-handle' tear of the meniscus is best recognized by which imaging feature?