[Diagnosis of primary sclerosing cholangitis: prospective comparison of MR cholangiography with endoscopic retrograde cholangiography].

To assess the accuracy of MR cholangiography (MRC) in the diagnosis of primary sclerosing cholangitis (PSC) in comparison to endoscopic retrograde cholangiography (ERC). 20 patients with PSC were examined by ERC and MRC (1.0 T, HASTE sequence). Visualization and pathologic changes of the extra- and intrahepatic bile ducts were evaluated with both methods. Mural irregularities of the common bile duct were seen with MRC in 6/7 cases, stenoses and dilatation of the common bile duct were detected correctly in all patients. Diffuse, multifocal strictures of the intrahepatic bile ducts were the most common intrahepatic findings and correctly diagnosed in almost all patients. Mural irregularities of the intrahepatic ducts in early stages may be missed by MRC because of the limited spatial resolution. MRC is superior to ERC in visualization of nonopacified intrahepatic ducts. MRC is a reliable, non-invasive method to detect typical diagnostic features of PSC. It should be considered as an adjunct to ERC in patients with suspected PSC for primary diagnosis and as an alternate method for follow-up studies.