Fourteen patients with hepatocellular carcinoma (HCC) were examined with computed tomography (CT) during arterial portography (CTAP) and with CT after intraarterial injection of iodized oil. The detectability of main lesions and associated daughter nodules or intrahepatic metastases was assessed. Hepatic resection was subsequently performed in all 14 patients. The results of the imaging studies were compared with the surgical and pathologic findings by means of a lesion-by-lesion analysis. A total of 34 masses were identified in the resected specimens: 18 main tumor masses and 16 intrahepatic metastases. For CTAP, the detection rate of main tumors was 94%; for iodized-oil CT, 82%. However, the daughter-nodule detection rates for both techniques were poor-only 38% detected for CTAP and 50% for iodized-oil CT. Although these two techniques remain important preoperative imaging methods in patients with HCC, the results of this study suggest that small daughter nodules (less than 5 mm in diameter) may go undetected with both techniques.