Anatomic Variation of Intrahepatic Bile Ducts in 300 Consecutive Liver Transplantation Donors on Intraoperative Cholangiograms LHD (Fig. 2). The RHD arises through fusion of the RASD, which drains anterior segments V and VIII, and the RPSD, which drains posterior segments VI and VII. Type 2 in- volves triple confluence, the simultaneous emptying of the RASD, RPSD and LHD into the common hepatic duct (CHD) (Fig. 3). Type 3, representing anomalous drainage of the RPSD, is subdivided into types 3A, 3B, and 3C, ac- cording to the drainage pattern of the RPSD. In type 3A, this drains into the LHD (Fig. 4a); in type 3B, into the CHD (Fig. 4b); and in type 3C, into the cystic duct. Type-4 IHD systems are those in which the RHD drains into the cystic duct (Fig. 5). Type 5, in which an accessory duct is present, is subdivided into types 5A and 5b according to the drainage pattern of duct: in type 5A, it drains into the CHD (Fig. 6a), and in type 5B, into the RHD (Fig. 6b). A type 6 is one in which segments II and III of the segmental duct drain individually into the RHD or CHD (Fig. 7), while a type 7 shows unclassified or complex variation (Fig. 8). The frequencies of each type were as the follows: type 1, 63% (n=188); type 2, 10% (n=29); type 3A, 11% (n=34); type 3B, 6% (n=19); type 3C, 2% (n=6), type 4, 0% (n=1); type 5A, 3% (n=8); type 5B, 3% (n=8); type 6, 1% (n=4); type 7, 1% (n=3). Fig. 2. Typical IHD anatomy (type 1). Operative cholangiogram shows that the CHD is formed by fusion of the RHD and LHD (as- terisks). The RHD is formed by fusion of the RASD (small ar- rows), which drains anterior segments V and VIII, and the RPSD (large arrows), which drains posterior segments VI and VII. Fig. 3. Triple confluence (type 2). Operative cholangiogram demonstrates simultaneous emptying of the RASD (small ar- rows), RPSD (large arrows) and LHD (asterisks) into the CHD. A B Fig. 4. Anomalous drainage of the RPSD (type 3). A. Drainage of the RPSD into the LHD (type 3A). B. Drainage of the RPSD into the CHD (type 3B). Each operative cholangiogram depicts drainage of the RPSD (large arrows) into the LHD (asterisk) and CHD, respectively. Small arrows=RASD Korean J Radiol 4(2), June 2003 87