Question:hard
Diagnosis of MRCP image.
Diagnosis of MRCP image.
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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.
Updated On: Jun 22, 2026
- GB Stone
- Cholangiocarcinoma
- Choledochal Cyst
- Gall and Blood Cancer
Show Solution
The Correct Option is B
Solution and Explanation
Approach the image as an obstructive-jaundice problem.
MRCP exploits the fact that bile is fluid: on a heavily $T2$-weighted sequence fluid is hyperintense, so the whole biliary tree is rendered bright. The diagnostic question on any MRCP is therefore: is the lesion a luminal defect (stone), a smooth dilatation (cyst/choledochal anomaly), or a stricture (tumour)?
What the picture tells us.
Beyond the gallbladder marked "GB", the duct shows a tight, irregular focal narrowing with the ducts above it ballooning out (proximal dilatation). A blockage that narrows the duct itself and dilates everything upstream is the signature of a wall-based ductal malignancy.
Mechanism of the answer.
A bile-duct adenocarcinoma (cholangiocarcinoma) grows in and around the duct wall, encasing and choking the lumen, which is why imaging shows an abrupt shouldered stricture plus upstream dilatation rather than a discrete pebble-like defect.
Eliminating the others.
$\bullet$ A gallbladder stone is an intraluminal signal void inside the GB, not a duct stricture.
$\bullet$ A choledochal cyst is a smooth, congenital fusiform widening of the common bile duct, usually in the young, with no obstructing tumour stricture.
$\bullet$ "Gall and Blood Cancer" is not a real diagnosis.
Hence the lesion is a cholangiocarcinoma (B).
MRCP exploits the fact that bile is fluid: on a heavily $T2$-weighted sequence fluid is hyperintense, so the whole biliary tree is rendered bright. The diagnostic question on any MRCP is therefore: is the lesion a luminal defect (stone), a smooth dilatation (cyst/choledochal anomaly), or a stricture (tumour)?
What the picture tells us.
Beyond the gallbladder marked "GB", the duct shows a tight, irregular focal narrowing with the ducts above it ballooning out (proximal dilatation). A blockage that narrows the duct itself and dilates everything upstream is the signature of a wall-based ductal malignancy.
Mechanism of the answer.
A bile-duct adenocarcinoma (cholangiocarcinoma) grows in and around the duct wall, encasing and choking the lumen, which is why imaging shows an abrupt shouldered stricture plus upstream dilatation rather than a discrete pebble-like defect.
Eliminating the others.
$\bullet$ A gallbladder stone is an intraluminal signal void inside the GB, not a duct stricture.
$\bullet$ A choledochal cyst is a smooth, congenital fusiform widening of the common bile duct, usually in the young, with no obstructing tumour stricture.
$\bullet$ "Gall and Blood Cancer" is not a real diagnosis.
Hence the lesion is a cholangiocarcinoma (B).
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