Biliary tract variations of the left liver with special reference to the left medial sectional bile duct in 500 patients

•The biliary anatomy of the left liver was evaluated in 500 patients using MR images.•The LHD was lacking in 6 patients (1.2%).•In these patients, the B4 entered the CHD or the right-sided sectional bile ducts.•The LHD was absent more frequently in patients with portal venous variations.

BackgroundAmong the intrahepatic bile ducts, the biliary system of the left medial sectional bile duct (B4) is known to have relatively complex patterns.MethodsThe records of 500 patients who had been diagnosed as having hepato-pancreatico-biliary disease were retrospectively studied for anatomical biliary variations of the left liver with special reference to the drainage system of B4 using magnetic resonance images.ResultsThe left hepatic duct was present in 494 patients (98.8%), whereas it was lacking in 6 patients (1.2%), and these patients exhibited the following B4 confluence patterns: B4 drained into the common hepatic duct in 2 patients (.4%), the right anterior sectional bile duct in 3 patients (.6%), and the right posterior sectional bile duct in 1 patient (.2%). The left hepatic duct was absent more frequently in patients with portal venous variations than in patients with a common branching pattern (8.2% vs .4%, P = .0011).ConclusionThe presently reported data are useful for obtaining a better understanding of the surgical anatomy of the biliary system of the left liver.