A novel mono-modality fusion imaging method based on three-dimensional contrast-enhanced ultrasound for the evaluation of ablation margins after microwave ablation of hepatocellular carcinoma.

Abstract

To investigate the feasibility and accuracy of using preoperative and postoperative three-dimensional contrast-enhanced ultrasound (3D CEUS) fusion imaging in the evaluation of safety margins after thermal ablation of hepatocellular carcinoma (HCC). A total of the 24 patients with HCC who underwent microwave ablation (MWA) between June 2020 and December 2020 were enrolled in this study. All patients received preoperative and postoperative 3D CEUS. The preoperative and postoperative 3D CEUS images were then fused. The success rate and evaluation time were recorded. The ablation margin and whether or not the safety margin was reached were calculated and recorded. If the ablation safety margin was not reached, the residual ablation volume needed to cover the safety margin was calculated automatically. The agreement between contrast-enhanced computed tomography(CECT) and 3D CEUS fusion imaging in the evaluation of ablation margins was explored using the kappa coefficient. The 3D CEUS fusion success rate was 95.8% (23/24), with a mean fusion time of (4.1±1.8) minutes. Twenty-three tumors were completely ablated, and the safety margin was achieved for 9 tumors. The ablation margin of 14 tumors was <5 mm. The mean uncovered safety margin volume was (2.27±2.11) mL, and the mean proportion of the uncovered safety margin to the whole safety margin was 16.8%. According to the results of preoperative and postoperative CECT fusion imaging, the ablation margin of 13 tumors was <5 mm, and the ablation margin of 10 tumors was >5 mm. The 2 methods showed excellent consistency, with a Kappa value of 0.911 (P=0.000012). This study has presented a novel mono-modality fusion imaging method based on CEUS. We demonstrated that 3D CEUS fusion has a short fusion time and a high success rate, as well as good consistency with enhanced CT fusion. Therefore, 3D CEUS fusion is a feasible and accurate tool for evaluating the immediate efficacy of thermal ablation of HCC.