Imaging Comparison of Lipiodol Retention after Transarterial Lipiodol Chemoembolization for Hepatocellular Carcinoma

Background and Purpose: The purpose of this study is to evaluate the change in echogeneity of hepatocelluar carcinomas (HCC) treated with transarteriallipiodol chemoembolization. Methods: Fifty-five cases with 86 HCCs were analyzed retrospectively. Forty-two tumors received transcatheter arterial chemoembolization (TACE), while the other 44 tumors received combination therapy of TACE and percutaneous ethanol injection (PEI) treatment. Results: All 86 tumors except 4 displayed changes in their sonographic echogeneity after the treatments. In the TACE-only group, post-treatment echogeneity of the lipiodol-retaining tumoral components were as follows: 40.5% hyperechoic, 9.5% isoechoic, 14.3% hypoechoic, and 35.7% mixed-echoic. In contrast, the echogeneity of non-lipiodol retaining parts were: 30% hyperechoic, 10% isoechoic, 50% hypoechoic, and 10% mixed-echoic. As for the combination therapy group, the echogeneity of its lipiodol-retaining parts were: 40.5% hyperechoic, 16.7% isoechoic, 11.9 hypoechoic, and 30.9% mixed-echoic. The non-lipiodol retaining parts' echogeneity were as follows: 32.3% hyperechoic, 19.4% isoechoic, 25.8% hypoechoic, and 22.5% mixed-echoic. Conclusion: There was significant difference in echogeneity between the lipiodol retaining and the non-lipiodol retaining components of the HCCs after treatment, in the TACE-only group. The majority of lipiodol-retaining tumor components were hyperechoic or mixed echoic, however the echogeneity of the lipiodol-retaining components from the combination therapy group was variable. Therefore the treatment efficacy of TACE, especially when used in conjunction with PEI, cannot be reliably assessed by ultrasonography alone.