Value of Lipiodol Computed Tomography and Digital Subtraction Angiography in the Era of Helical Biphasic Computed Tomography as Preoperative Assessment of Hepatocellular Carcinoma

Abstract

ObjectiveTo compare the diagnostic accuracies of Lipiodol computed tomography (CT) and helical biphasic CT as preoperative imaging modalities for hepatocellular carcinoma (HCC). Summary Background DataLipiodol CT after digital subtraction angiography has long been used as a highly sensitive imaging modality for HCC. The recent advent of helical CT has allowed scanning the entire liver during both the arterial and portal venous phase of contrast enhancement. MethodsThe 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 confirmation were set as the gold standard. ResultsAlthough sensitivity decreased with both modalities as tumors became small and well differentiated, helical CT showed a higher sensitivity than Lipiodol CT in detecting well-differentiated HCC nodules smaller than 2 cm. In contrast, Lipiodol CT was superior to helical CT for the detection of small but moderately to poorly differentiated nodules. The overall sensitivity of helical CT was higher than that of Lipiodol CT. These findings suggest that helical CT is superior in delineating early HCC, whereas Lipiodol CT is specific to the detection of intrahepatic metastases. In terms of specificity, helical CT was superior to Lipiodol CT. ConclusionsHelical CT and Lipiodol CT are complementary modalities. At present, helical biphasic CT does not obviate the need for invasive techniques such as angiography and Lipiodol CT as preoperative examinations for HCC.Advances in various imaging modalities including ultrasonography and computed tomography (CT) have facilitated the detection of hepatocellular carcinoma (HCC) in a preclinical stage.1 As a result, the resectability of HCC has markedly increased, thereby significantly improving survival during the past two decades.2-5 HCC nodules are often multifocal and frequently accompanied by intrahepatic metastatic nodules.6 -8 Underestimation of these lesions may lead to inappropriate surgical resection. Therefore, accurate preoperative imaging evaluation of HCC nodules is essential for selecting appropriate patients for surgical intervention and for determining the extent of hepatectomy. Because typical HCCs are hypervascular tumors that have only an hepatic arterial blood supply (i.e., there is no portal venous

Management of Hepatocellular Carcinoma in Japan: Consensus-Based Clinical Practice Guidelines Proposed by the Japan Society of Hepatology (JSH) 2010 Updated Version

“…Diagnosis of HCC by angiography including DSA is 69.0%, lower than that (86.9%) of helical CT [50]. Also, detectability more markedly decreases than does CT sensitivity when the tumor size is small.…”

Management of Hepatocellular Carcinoma in Japan: Consensus-Based Clinical Practice Manual Proposed by the Japan Society of Hepatology

“…Angiography of HCC by angiography including DSA is 69.0%, lower than that (86.9%) of helical CT [14]. Besides, detectability more markedly decreases than does CT sensitivity when the tumor size is small.…”

Sequential Transcatheter Arterial Chemoembolization and Portal Vein Embolization for Hepatocellular Carcinoma: The University of Tokyo Experience

“…In the first phase of the CT performed without a contrast medium (Lipiodol-CT), we check for the presence of any tumor nodules in the nonembolized segments. 25 The presence of iodized oil deposition, which is compatible with HCC nodules, that could not be detected in the initial contrast-enhanced CT scans obtained before PVE indicates a high likelihood of intrahepatic metastasis, and therefore curative resectional surgery may be difficult to expect. 25 Then, we recalculate the volumes of the embolized and nonembolized segments and of the tumor(s).…”

“…The latter possibility should always be borne in mind because large HCCs in the right lobe, which frequently constitute an indication for PVE, are often adjacent to the diaphragm, which makes the right inferior phrenic artery the major extrahepatic collateral artery, although this cannot be recognized unless selective angiography of this branch is performed. 24 Finally, iodized oil is administered intra-arterially into the branches of the nonembolized segments to enable intrahepatic metastases to be detected by subsequent CT. 25 We perform PVE when the conventional liver function test results (i.e., the serum aspartate transaminase [AST], alanine transaminase [ALT], and total bilirubin levels) stabilize after the TACE, usually 7 to 10 days after the procedure in most cases (Fig. 1C).…”