Anatomic Variation in Intrahepatic Bile Ducts: an Analysis of Intraoperative Cholangiograms in 300 Consecutive Donors for Living Donor Liver Transplantation Jin Woo Choi, MD Tae Kyoung Kim, MD Kyoung Won Kim, MD Ah Young Kim, MD Pyo Nyun Kim, MD Hyun Kwon Ha, MD Moon-Gyu Lee, MD Index terms : Bile ducts, anatomy Bile ducts, abnormalities Bile ducts, radiography Korean J Radiol 2003;4:85-90 Received October 9, 2002; accepted after revision March 25, 2003. All authors; Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea. Address reprint requests to: Tae Kyoung Kim, MD, Department of Diagnostic Radiology, Asan Medical Center, University of Ulsan College of Medicine, 388-1 Poongnap-dong, Songpa- gu, Seoul 138-736, Korea. Telephone: (822) 3010-4400 Fax: (822) 476-4719, e-mail: tkkim@amc.seoul.kr Korean J Radiol 4(2), June 2003 Objective: To describe the anatomical variation occurring in intrahepatic bile ducts (IHDs) in terms of their branching patterns, and to determine the frequency of each variation. Materials and Methods: The study group consisted of 300 consecutive donors for liver transplantation who underwent intraoperative cholangiography. Anatomical variation in IHDs was classified according to the branching pattern of the right anterior and right posterior segmental duct (RASD and RPSD, respec- tively), and the presence or absence of the first-order branch of the left hepatic duct (LHD), and of an accessory hepatic duct. Results: The anatomy of the intrahepatic bile ducts was typical in 63% of cases (n=188), showed triple confluence in 10% (n=29), anomalous drainage of the RPSD into the LHD in 11% (n=34), anomalous drainage of the RPSD into the common hepatic duct (CHD) in 6% (n=19), anomalous drainage of the RPSD into the cystic duct in 2% (n=6), drainage of the right hepatic duct (RHD) into the cys- tic duct (n=1), the presence of an accessory duct leading to the CHD or RHD in 5% (n=16), individual drainage of the LHD into the RHD or CHD in 1% (n=4), and unclassified or complex variation in 1% (n=3). Conclusion: The branching pattern of IHDs was atypical in 37% of cases. The two most common variations were drainage of the RPSD into the LHD (11%) and triple confluence of the RASD, RPSD and LHD (10%). W hen radiologists interpret a cholangiogram or perform percutaneous drainage of the bile duct, anomalous drainage of the segmental biliary ducts can lead to difficulties in opacification or drainage of the entire duc- tal system (1). Surgical procedures such as liver resection and partial liver transplanta- tion are, moreover, increasing in frequency and complexity (2 4), and in hepatic re- section for living donor liver transplantation (LDLT), an accurate knowledge of the anatomy of intrahepatic bile ducts (IHDs) is thus critical if the liver is to be successfully harvested and postoperative complications minimized (2, 3, 5). While several reports have described the anatomic variation in IHDs seen at direct or MR cholangiography, they have included patients in whom pancreatobiliary disease was suspected. The purpose of this study is to describe anatomic variation in IHDs in terms of the branching patterns observed, and to determine the frequency of each variation. To this end, we retrospectively evaluated the intraoperative cholangiograms of 300 consecu- tive living donors for liver transplantation. 85