In order to evaluate diagnostic effectiveness of the infusion-study, the authors prospectively evaluated hepatic digital subtraction angiography of bolus and infusion studies in 71 patients with hepatocellular carcinoma. In contrast to Bolus-DSA, which involves a 2 second injection of 10cc of contrast medium, the Infusion-DSA uses a protracted(10sec) injection, a lower injection rate, and larger total dose of contrast medium(20cc). The information yield of arterial and capillary phases of Infusion-DSA was compared with that of Bolus-DSA and graded as "improved(+)", "equivalent($pm$)", or "poor(-)" Also, the contribution of Infusion-DSA to the diagnosis was classified into one of five in a graded system. In 29 hepatocellular patients, the Infusion-DSA was helpful in detecting daughter nodules, fibrous capsule and arteriovenous shunt. Infusion-DSA is a useful complementary technique in the diagnosis of hepatocellular carcinoma and was also helpful in determining the selection of the therapeutic modality of hepatocellular carcinoma.y of hepatocellular carcinoma.