Differential Diagnosis of Pancreaticobiliary Ductal and Duodenal Union Carcinomas with MRI 3D-VIBE Sequence Combined with MRCP

OBJECTIVE:To evaluate the value of MRI 3-dimensional volumetric interpolated breath-hold examination (VIBE) sequence combined with MR cholangiopancreatography (MRCP) in the differential diagnosis of pancreaticobiliary ductal and duodenal union carcinomas (PDDUC). METHODS:Fifty nine patients with PDDUC confirmed by surgical-pathological findings or unequivocal clinical follow-up results were recruited in the study, which included 34 pancreatic head carcinomas, 14 distal common bile duct carcinomas, and 11 ampullary carcinomas. In addition to the routine MRI examinations for the upper abdomen, MRCP and Gadolinium-enhanced 3D-VIBE tri-phase (early arterial phase, late arterial phase and portal venous phase) were performed. The morphological features of the lesions, the signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of the lesions were analyzed. The distance between the ends of the dilated pancreaticobiliary duct, the distance from the duodenal lumen to the distal end of the dilated duct, the diameter of the common bile duct and the pancreatic duct were measured. RESULTS:The differences among the carcinomas in max-diameters, locations, edge features and degrees of signal equality of the lesions showed statistical significance (P < 0.05). The percentage of peripancreatic vascular involvement was significantly higher in the pancreatic head carcinoma than in the others. The pancreaticobiliary conjunction angle, the distance between the ends of dilated pancreaticobiliary ducts, the distance from the duodenal lumen to the distal end of dilated duct were larger in the pancreatic head carcinoma than in the distal common bile duct carcinoma and ampullary carcinoma. The pancreatic head carcinoma showed four-segment signs. During portal venous phase, the mean SNR of the distal common bile duct carcinoma was higher than the pancreatic head carcinoma and ampullary carcinoma (P < 0.05), while in the other phases, no statistical significant differences were found (P > 0.05). The signal intensity of distal common bile duct carcinoma was higher than the pancreatic head parenchyma during portal venous phase. CONCLUSION:MRI 3D-VIBE sequence combined with MRCP can demonstrate the morphologic features and enhancement characteristics of PDDUC, and display the details of abnormalities of pancreaticobiliary duct. It is valuable in the differential diagnosis of pancreatic head carcinoma, distal common bile duct carcinoma and ampullary carcinoma.