Five of six patients with angiographically proved Budd-Chiari syndrome (hepatic venous outflow obstruction) showed multiple specific MRI abnormalities: striking reduction in caliber or complete absence of the hepatic veins, "comma-shaped" intrahepatic collateral vessels, and/or marked constriction of the intrahepatic inferior vena cava. The sixth patient had angiographically proven sinusoidal hepatic venous obstruction and patent central hepatic veins; MRI showed ascites but revealed no specific features of the Budd-Chiari syndrome. Patients with end-stage cirrhosis also showed compressed, distorted hepatic veins; however, these cirrhotic livers were distinguished by their small size, nodular surface, and extrahepatic collateral varices. In patients without cirrhosis or the Budd-Chiari syndrome, normal hepatic, portal, and inferior caval veins were routinely seen when technically adequate MRI examinations were obtained (94 of 100 cases). Four of the six patients with Budd-Chiari syndrome had been treated surgically. In three, MRI identified patent portocaval shunts. In the fourth, angiographically confirmed shunt stenosis was demonstrated by MRI.