On MRCP, which finding is MOST characteristic of primary sclerosing cholangitis (PSC)?
- A Smooth tapering stricture of the CBD with upstream dilatation
- B Single dominant stricture at the hilum with upstream dilatation
- C Multifocal beading with alternating strictures and dilations of intra- and extrahepatic bile ducts ✓
- D Distal CBD stricture with double-duct sign
Correct answer: C. Multifocal beading with alternating strictures and dilations of intra- and extrahepatic bile ducts
Explanation
PSC is characterized on MRCP by multifocal irregular strictures alternating with normal or mildly dilated segments throughout both intra- and extrahepatic bile ducts, giving a 'beaded' appearance. This diffuse multifocal pattern distinguishes PSC from other biliary strictures. A smooth tapered CBD stricture is more typical of chronic pancreatitis. A dominant hilar stricture (Klatskin-type) without multifocal disease may suggest cholangiocarcinoma complicating PSC. The double-duct sign (dilated CBD + pancreatic duct) suggests carcinoma of the head of pancreas.
Reference: Grainger & Allison's Diagnostic Radiology, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.