Choledocholithiasis and bile duct stenosis: diagnostic accuracy of MR cholangiopancreatography.

PURPOSE: To evaluate the accuracy of magnetic resonance (MR) cholangiopancreatography for detecting bile duct calculi and stenosis. MATERIALS AND METHODS: At MR cholangiopancreatography, 108 patients suspected of having bile duct calculi or stenosis were examined with two-dimensional fast spin-echo MR sequences and respiratory gating. On the basis of findings at surgery and/or intraoperative, endoscopic retrograde, and/or percutaneous cholangiography, final diagnoses were normal bile ducts (n = 38), choledocholithiasis (n = 23), Mirizzi syndrome (n = 3), benign or malignant bile duct stenosis (n = 40), choledochal cyst (n = 1), and bile duct dilatation without calculi or stenosis (n = 3). MR cholangiopancreatographic images were analyzed retrospectively by three reviewers who were unaware of final diagnoses. RESULTS: Choledocholithiasis was diagnosed with a sensitivity of 88%-92% and a specificity of 91%-98%. False-negative readings occurred because small or impacted calculi at the distal common bile duct or ampulla were difficult to detect or distinguish from stenosis. Bile duct stenosis was diagnosed with a sensitivity of 93%-100% and a specificity of 98%. Presence or absence of bile duct abnormality was assessed with a sensitivity of 97%-99% and a specificity of 95%-97%. Interobserver agreement was very good (kappa = 0.86-0.96). CONCLUSION: With MR cholangiopancreatography, bile duct calculi and stenoses can be diagnosed with high accuracy and good interobserver agreement.