Utility of Contrast‐Enhanced Ultrasound for Early Therapeutic Evaluation of Hepatocellular Carcinoma After Transcatheter Arterial Chemoembolization

Objectives We aimed to investigate whether contrast‐enhanced ultrasound (CEUS) could be useful for early evaluation of the treatment response to transcatheter arterial chemoembolization (TACE) of hepatocellular carcinoma (HCC). Methods This study retrospectively selected HCCs in which homogeneous retention of iodized oil was confirmed on non–contrast‐enhanced computed tomography performed immediately after TACE. Therapeutic responses of HCCs were evaluated by CEUS 1 to 2 days after TACE and by contrast‐enhanced computed tomography (CECT) approximately 4 weeks after TACE. We investigated the noninferiority of CEUS 1 to 2 days after TACE to CECT approximately 4 weeks after TACE in terms of the diagnostic accuracy of the therapeutic response to TACE on HCC. Results Eighty‐nine HCCs were enrolled in this study between April 2014 and June 2016. A complete response was observed in 57 of 89 nodules (64.0%), and an incomplete response was observed in the remaining 32 nodules (36.0%). The accuracy rates for CEUS 1 to 2 days after TACE and CECT approximately 4 weeks after TACE in the therapeutic effect of TACE on HCCs were 83.1% (95% confidence interval, 73.7%–90.2%) and 83.1% (95% confidence interval, 73.7%–90.2%), respectively. The difference in diagnostic accuracy between methods was 0%, which was below the predetermined noninferiority limit of 15%, and CEUS 1 to 2 days after TACE was noninferior to CECT approximately 4 weeks after TACE. Conclusions Our results suggest that CEUS is a useful modality for early therapeutic evaluation of TACE for HCC, and we can thus plan the next treatment strategies for HCC within a few days after TACE.