Analysis of biliary anatomy according to different classification systems.

Purpose: Variations in biliary anatomy are common, and different classifications have been described. These classification systems have not been compared to each other in a single cohort. We report such variations in biliary anatomy on magnetic resonance cholangiopancreatography (MRCP) using six different classification systems.

Methods: In 299 patients undergoing MRCP for various indications, biliary anatomy was classified as described by Couinaud (1957), Huang (1996), Karakas (2008), Choi (2003), Champetier (1994), and Ohkubo (2004). Correlation with direct cholangiography and vascular anatomy was done. Bile duct dimensions were measured. Cystic duct junction and pancreaticobiliary ductal junction (PBDJ) were classified.

Results: Normal biliary anatomy was noted in 57.8 %. The most common variants were Couinaud type D2, Choi type 3A, Huang type A1, Champetier type a, Ohkubo types D and J, and Karakas type 2a. The Ohkubo classification was the most appropriate; 3.1 % of right ducts and 6.3 % of left ducts with variant anatomy could not be classified using the Ohkubo classification. There was a good agreement between MRCP and direct cholangiography (ĸ = 0.9). Anomalous PBDJ was noted in 8.7 %. Variant biliary anatomy was not associated with gender (p = 0.194) or variant vascular anatomy (p = 0.24).

Conclusion: Although each classification system has its merits and demerits, some anatomical variations cannot be classified using any of the previously described classifications. The Ohkubo classification system is the most applicable as it considers most clinically relevant variations pertinent to hepatobiliary surgery.