PURPOSE: To determine the accuracy of preoperative MR imaging for evaluation of resectability of extrahepaticbile duct carcinoma. MATERIALS AND METHODS: Thirty-four patients with proven extrahepatic bile duct carcinomaunderwent pre-operative MR imaging. All MR examinations were performed with a 1.5 T system, using a phased-arraymulticoil. Tumor resectability was prospectively determined by two radiologists who reached consensus. Tenpatients did not undergo surgery because the preoperative MR imaging, CT and endoscopic findings all indicatedunresectability. Twenty-five patients subsequently underwent surgical exploration, and their imaging andpathologic and laparotomic findings were compared. RESULTS: Twenty-two of 34 cases (65%) were resectable. Amongthe 22 cases resectable in laparotomy, pre-operative MR imaging had suggested that 20 were resectable, andsensitivity for resectability was thus 91%. Among the 22 cases in which MR imaging had suggested resectability,macroscopic clearance was complete in 20, giving a positive value of 91%. MR imaging underestimated portal venousor hepatic arterial invasion, and in one case missed small (<1 cm) hepatic metastases. In two cases, MR imagingoverestimated portal venous or hepatic arterial encasement. CONCLUSION: MR imaging is a useful diagnosticmodality for preoperative assessment of resectability of extrahepatic bile duct cancer.