Abstract：Objective: To investigate the value of conventional magnetic resonance imaging(MRI) and magnetic resonance cholangiopancreatography(MRCP) in diagnosing biliary tract obstruction by malignant tumor as well as correlate with pathology. Methods: Forty-six cases were included in this study, MRCP were performed following T1WI, T2WI and fat-saturation T2WI in each case. Conventional MRI and MRCP appearances of dilatation of bile duct in different locations were compared to its pathology. Results: In 46 cases of malignant biliary tract obstruction, hyperintense signals on T2WI and intrahepatic bile duct dilation on MRCP can be observed in 4 cases, their pathological exams confirmed to be cholangiocarcinoma of the intrahepatic bile duct; hilar defect-sign with proximal bile duct dilation on MRCP in 10 cases of which hyperintense signal mass on T2WI in 7 cases, their pathological exams showed extrahepatic bile duct carcinoma(6 cases) and gallbladder carcinoma(4 cases) by pathology. In 16 cases, abrupt obstruction of middle segment of common bile duct on MRCP of which 6 cases have slight hyperintense signals on T2WI, their pathological exams showed extrahepatic bile duct carcinoma(9 cases) gallbladder carcinoma(3 cases); pancreatic head carcinoma(2 cases); and adenocarcinoma of the duodenum(2 cases). Obstruction or stenosis of distal common bile and pancreatic duct dilation on MRCP can be seen in 16 cases, and only 8 cases of which had slight hyperintense signals on T2WI. their pathological exams proved to be pancreatic head carcinoma(4 cases) and ampullary adenocarcinoma of the duodenum(4 cases) and common bile duct carcinoma(3 cases) and carcinoma of ampulla Vater（5 cases）. Conclusion: Different features of MRCP and MRI can be demonstrated in biliary tract obstruction with malignant tumor, which were related to their pathology. Combination of MRI and MRCP can help the diagnosis of biliary tract obstruction with malignant tumor.
2007, Vol. 18 
