Small hepatocellular carcinoma. Detection with US, CT, MR imaging, DSA, and Lipiodol-CT.

Twenty-two patients with 37 small (3 cm or less) nodular lesions of hepatocellular carcinoma (HCC) were examined with ultrasonography (US), CT, MR imaging, digital subtraction angiography (DSA), and CT following intraarterial injection of Lipiodol (Lipiodol-CT). All patients subsequently underwent surgery, and the gold standard was provided by intraoperative US. The detection rate was 70% for US, 65% for CT, 62% for MR imaging, 73% for DSA, and 86% for Lipiodol-CT. A significant difference (p < 0.05) was observed between the detection rate of Lipiodol-CT and the detection rates of all the other imaging modalities. The difference was even more manifest (p < 0.02) when only lesions smaller than or equal to 1 cm were considered. It is concluded that Lipiodol-CT is the single most sensitive examination to detect small nodules of HCC. It should therefore be considered a mandatory step in the preoperative evaluation of patients with HCC considered to be surgical candidates after noninvasive imaging studies.