Value of lipiodol computed tomography and digital subtraction angiography in the era of helical biphasic computed tomography as preoperative assessment of hepatocellular carcinoma

Objective To compare the diagnostic accuracies of Lipiodol computed tomography (CT) a nd helical biphasic CT as preoperative imaging modalities for hepatocellula r carcinoma (HCC). Summary Background Data Lipiodol CT after digital subtraction angiography has long been used as a h ighly sensitive imaging modality for HCC. The recent advent of helical CT h as allowed scanning the entire liver during both the arterial and portal ve nous phase of contrast enhancement. Methods The authors analyzed data from 164 patients who underwent hepatic resection for HCC to calculate the sensitivity and specificity of these modalities. Findings of intraoperative ultrasonography followed by histologic confirmat ion were set as the gold standard. Results Although sensitivity decreased with both modalities as tumors became small and well differentiated, helical CT showed a higher sensitivity than Lipiod ol CT in detecting well-differentiated HCC nodules smaller than 2 cm. In co ntrast, Lipiodol CT was superior to helical CT for the detection of small b ut moderately to poorly differentiated nodules. The overall sensitivity of helical CT was higher than that of Lipiodol CT. These finding suggest that helical CT is superior in delineating early HCC, whereas Lipiodol CT is spe cific to the detection of intra hepatic metastases. In terms of specificity , helical CT was superior to Lipiodol CT. Conclusions Helical CT and Lipiodol CT are complementary modalities. At present, helica l biphasic CT does not obviate the need for invasive techniques such as ang iography and Lipiodol CT as preoperative examinations for HCC.