Question

Diagnosis of MRCP image.

• A. GB Stone
• B. Cholangiocarcinoma
• C. Choledochal Cyst
• D. Gall and Blood Cancer

Hint:

On MRCP, an abrupt irregular ductal stricture with upstream dilatation points to a tumour of the duct wall, not a stone or a smooth congenital cyst.

Answer 1

The Correct Option is B

Step 1: Understand the modality. MRCP (Magnetic Resonance Cholangiopancreatography) is a non-invasive heavily T2-weighted MRI sequence in which static or slow-moving fluid (bile and pancreatic juice) appears bright white, so it maps the biliary and pancreatic ducts like a contrast cholangiogram without injecting contrast.

Step 2: Interpret the image. The labelled gallbladder (GB) is seen, but the key abnormality is an abrupt focal narrowing/cut-off (stricture) of the bile duct with upstream dilatation of the intrahepatic ducts, producing the classic obstructive pattern of a malignant ductal stricture rather than a simple filling defect.

Step 3: Why option B (Cholangiocarcinoma) is correct. Cholangiocarcinoma is an adenocarcinoma of the bile duct epithelium. On MRCP it characteristically shows an irregular, abrupt ductal stricture with proximal biliary dilatation (the \(\text{"double-duct"}\) or shouldered cut-off sign for distal lesions), exactly the obstructive ductal appearance shown.

Step 4: Why the distractors are wrong. (A) GB Stone (cholelithiasis) would show a rounded T2-hypointense signal-void filling defect within the gallbladder lumen, not a ductal stricture. (C) Choledochal cyst produces smooth fusiform or saccular cystic dilatation of the common bile duct without an obstructing stricture, and is typically diagnosed in younger patients. (D) "Gall and Blood Cancer" is not a recognised radiological/clinical entity.

Final Answer: Option B - Cholangiocarcinoma.