Membranous obstruction of the inferior vena cava: comparison of findings at sonography, CT, and venography

Membranous or segmental obstruction of the inferior vena cava is one of the common causes of chronic Budd-Chiari syndrome. In this study, the venographic findings are compared with the results of sonography and CT in order to ascertain their role in the management of these cases. Fifteen patients with membranous (n = 8) or segmental (n = 7) obstruction of the inferior vena cava who had been examined with sonography and CT were studied retrospectively. Diagnosis was made at surgery (n = 3) or by venacavography (n = 12). Sonographic findings were analyzed on the basis of the initial report, and CT findings were reviewed retrospectively with knowledge of the sonographic findings. Sonography showed membranous obstruction (n = 5), segmental cordlike obstruction (n = 3), and unspecified obstruction (n = 5) of the inferior vena cava, while CT showed a flap of the membrane (n = 1) and segmental narrowing or obstruction of the inferior vena cava (n = 7). In the remaining cases, the inferior vena cava either appeared normal (n = 6) or was not visualized (n = 1) on CT or was not described in the sonographic report (n = 2). In nine cases, CT showed one or several tiny calcific foci in the inferior vena cava. Sonography showed obliteration of at least one hepatic vein (n = 8) and of intrahepatic collateral vessels (n = 12), whereas CT was less sensitive in evaluating obliteration of intrahepatic veins (n = 4) and collateral vessels (n = 7). Sonography and CT both showed hepatic masses (n = 6), evidence of liver cirrhosis and portal hypertension (n = 14), hepatomegaly (n = 14), enlargement of the caudate lobe (n = 9), and intraabdominal (n = 11) and abdominal wall (n = 15) collateral vessels. Sonography was superior to CT in delineating pathologic venous anatomy of the inferior vena cava and hepatic veins whereas CT was better in evaluating hepatic cirrhosis and tumor. We believe that these techniques are useful complements to venography in the diagnosis and management of these cases.