Malignant perihilar biliary obstruction: magnetic resonance cholangiopancreatographic findings.

We studied the efficacy of magnetic resonance cholangiopancreatography (MRCP) in the evaluation of malignant perihilar biliary obstructions, with reference to endoscopic retrograde cholangiopancreatography (ERCP). A total of 40 patients with malignant perihilar biliary obstructions, who underwent both MRCP (Magnetom Vision; Siemens, Erlangen, Germany; projection technique and multislice plus maximum intensity projection) and ERCP examinations, were studied. The study group included hilar cholangiocarcinoma (Klatskin tumor) in 26 patients, icteric hepatocellular carcinoma in four patients, gallbladder carcinoma in five patients, and metastasis from other than hepatobiliary origin in five patients. Axial and coronal magnetic resonance (MR) images were added simultaneously to the MRCP. The mean serum bilirubin level on admission was 11.5 mg/ml (range, 2.8-28.5 mg/ml). The presence and extent of malignant biliary obstruction were determined with both MRCP and ERCP following the known criteria: an abrupt and irregular character of a distal narrow segment, a proportionally dilated biliary tree proximally, and an irregularly shaped intraluminal filling defect. The efficacy of the MRCP examination in detecting the presence of biliary obstruction, its anatomical extent, and the underlying cause, respectively, was compared to that of ERCP. MRCP examination was successfully performed on all patients, whereas ERCP examination was unsuccessful in two patients. Both MRCP and ERCP were very effective in detecting the presence of biliary obstructions (40 of 40 vs. 38 of 38, p = 1.0). MRCP was superior in its investigation of anatomical extent (34 of 40 vs. 24 of 38, p = 0.015) and the cause of the jaundice (31 of 40 vs. 22 of 38, p = 0.023) compared to ERCP. Specifically, the performance of MRCP is promising for the interpretation of cholangiocarcinoma (22 of 26) and gallbladder carcinoma (five of five), but is relatively ineffective for the interpretation of icteric HCC (two of four) and metastasis (two of five). MRCP represented an ideal noninvasive diagnostic tool for the evaluation of malignant perihilar biliary obstructions with reference to ERCP.