Figure 20b.  Ischemic changes of the bile duct in a 43-year-old man 6 months after orthotopic liver transplantation. (a) MR cholangiogram demonstrates smooth narrowing of the common hepatic duct and the central intrahepatic bile ducts (arrows). The more peripheral branches of the intrahepatic bile ducts are dilated. (b) Endoscopic retrograde cholangiogram shows narrowing of the right hepatic duct (arrow); the narrowing of the left hepatic duct is obscured by overlying ducts.