Efficacy of Fusion Imaging and Cone-Beam Computed Tomography-Guided Radiofrequency Ablation for Hepatocellular Carcinoma Poorly Visualized on Ultrasonography.

[INTRODUCTION] Radiofrequency ablation (RFA) generally involves the insertion of a radiofrequency electrode into the hepatocellular carcinoma (HCC) nodule under ultrasonography (US) guidance. However, the procedure is often not feasible for patients whose HCC is undetectable on conventional US. Advances in imaging technology, such as fusion imaging (FI) and cone-beam computed tomography (CBCT), may enhance treatment precision and efficacy for these challenging cases. This study assessed the efficacy of RFA guided by FI and CBCT in managing HCC poorly visualized on US.

[METHODS] HCC nodules were classified into GOOD (clearly delineated), POOR (poorly delineated), and NONE (undetectable) based on US visualization. All nodules underwent RFA guided by FI and CBCT either in combination with transcatheter arterial chemoembolization (TACE) or without TACE. The technical success rate and local tumor progression post-RFA were evaluated using dynamic contrast-enhanced imaging. Between-group differences were analyzed retrospectively.

[RESULTS] A total of 420 patients with 595 HCC nodules were enrolled. Complete ablation rates were 91.4%, 94.9%, and 86.2% in the GOOD, POOR, and NONE groups, respectively. For nodules with over 50% lipiodol accumulation, the complete ablation rates were 91.5%, 96.5%, and 88.8%; for those with less than 50% lipiodol accumulation, they were 95.5%, 100%, and 62.5%; and for those without lipiodol accumulation, they were 89.5%, 77.8%, and 82.4% in the GOOD, POOR, and NONE groups, respectively. Significant factors associated with complete ablation included larger nodule size and lipiodol accumulation. Cumulative local tumor progression rates at 1 year were 4.5%, 0%, and 3.8%, with no significant differences among groups.

[CONCLUSION] FI and CBCT guidance effectively achieve local control for HCC, including nodules poorly visualized on US, with outcomes comparable to US-visible nodules, especially for those with lipiodol accumulation.