CT diagnosis of primary Budd-Chiari syndrome--membranous obstruction of the inferior vena cava.

Five cases with primary Budd-Chiari syndrome due to membranous obstruction of the hepatic segment of the inferior vena cava were examined by CT. In all cases, CT demonstrated caudate lobe enlargement, reticular low density within the liver parenchyma, splenomegaly, and collaterals via the ascending lumbar veins and azygous system. Pathological study revealed liver cirrhosis or fibrosis in all cases. In two cases, calcification was shown in the region of the hepatic segment of the inferior vena cava. Our results suggested that the CT appearance of primary Budd-Chiari syndrome was rather characteristic and useful in diagnosis, although membranous obliteration could not be shown directly on CT.