Anatomic variants of the biliary tree with MR Cholangiography: feasibility and surgical applications

PURPOSE: To assess the usefulness of MR Cholangiography for evaluation of anatomic variants of the biliary tree before biliary surgery. MATERIALS AND METHODS: Our study group consisted of 45 consecutive patients (29 males, 16 females; mean age 57 years), who were referred for MR evaluation of malignant (n=26) and benign (n=19) cholangiopancreatic diseases. MR Cholangiography studies were independently reviewed by two radiologists. RESULTS: Anatomic variants of the biliary tree were observed in 9 patients (20%); 6 variants involved the biliary confluence and 4 the cystic duct (one patient had both). Anatomic variants involved principally the right posterior duct: 1 (2,2%) drainage of right posterior duct into left hepatic duct; 2 (4,4%) triple confluence of right posterior duct, right anterior duct, and left hepatic duct, and 3 (6,6%) aberrant drainage of right posterior duct into common hepatic duct. Observed cystic duct anomalies included: 2 (7,44%) low insertion of the cystic duct into the common hepatic duct and 3 (11,1%) medial insertion of the cystic duct into the common hepatic duct. CONCLUSION: MR Cholangiography accurately shows anatomic variants of the biliary tree. Noninvasive preoperative evaluation of the biliary anatomy may be important for the detection of anatomic variants that may increase the complexity of hepatic surgical procedures and biliary interventions.