Figure 14b.  Primary sclerosing cholangitis in a 51-year-old woman with increasing alkaline phosphatase levels. (a) MR cholangiogram shows stenosis of a right hepatic duct branch (arrows). (b) MR cholangiogram demonstrates stenoses and irregularities of the left hepatic ducts (arrows), indicative of primary sclerosing cholangitis, as well as third-order bile ducts (arrowheads).