Intrahepatic biliary duct branching patterns, cystic duct anomalies, and pancreas divisum in a tertiary referral center: A magnetic resonance cholangiopancreaticographic study.

BACKGROUND: Knowledge about anatomic variations in intrahepatic biliary ducts (IHBD) is relevant for performing biliary drainage and for avoiding bile duct injury during cholecystectomy and liver resections. Low insertion of cystic duct (LICD) is a common anatomic variant. Pancreas divisum is the commonest congenital anomaly of pancreas; it has been causally linked with recurrent acute pancreatitis (RAP).

METHODS: Magnetic resonance cholangiopancreaticography (MRCP) images of 500 consecutive patients were reviewed for anatomic variants of IHBD, cystic duct, and pancreatic duct.

RESULTS: Anatomy of IHBD could be evaluated in 458 MRCP's, of these 301 (65.72 %) had 'typical' anatomy. The variant in 157 persons included 'triple confluence' in 56 (12.23 %), 'right posterior segmental duct (RPSD) draining to left hepatic duct (LHD)' in 64 (14 %), 'RPSD to common hepatic duct (CHD)' in 20 (4.4 %), 'RPSD to cystic duct' in 2 (0.4 %), 'accessory duct to CHD' in 3 (0.7 %), 'accessory duct to right hepatic duct (RHD)' in 1 (0.2 %), 'segment 2 and 3 separately to CHD' in 1 (0.2 %), and complex variants in 10 (2.2 %). Cystic duct could be evaluated in 338 patients; of these, 15 (4.4 %) had LICD. Patients with RAP had pancreas divisum more often than those without any pancreatic disease, (-/-,10 % and -/-, 0.8 %; p = 0.004).

CONCLUSIONS: Nearly one third of MRCPs showed atypical IHBD pattern with RPSD draining to LHD being the commonest. LICD was the most common cystic duct variant. Pancreas divisum was more frequent in patients with RAP than in persons without pancreatic disease.