A New-Designed Microwave Ablation System: Testing in ex vivo and in vivo Liver Model

Abstract

Objective: The present study aimed to determine the efficacy and safety of a newly designed microwave ablation (MWA) system in ex vivo and in vivo liver model.Methods: A new MWA system (HRMW-01, Hengrui Medical, Guangzhou, China) was tested on porcine liver ex vivo with different parameter settings (50-70 W for 5-20 min). Ablation volums were measured on the gross specimens. In an in vivo study, MWA was performed at 60 W for 5 min in canine liver. Ablation volumes were identified and measured using contrast-enhanced ultrasound (CEUS) 1 w after the ablation. All animals underwent routine hematological, biochemical, and coagulation tests before ablation at 1 d and 1 w after ablation. For comparison, radiofrequency ablation (RFA) was performed using a Cool-tip system (Valleylab, Boulder, CO, USA) with an automated power setting for 12 min in both ex vivo and in vivo studies. Results: In ex vivo studies, the mean volumes of MWA coagulation ranged from 27.8 ± 7.3 cm3 to 144.6 ± 35.9 cm 3 and increased with ablation duration and power output. MWA was prone to creating larger volume but less spherical ablation shape than RFA (P < 0.05). In in vivo studies, MWA created larger ablation volumes with shorter ablation time compared to RFA (P < 0.05). Laboratory data showed significantly higher alanine aminotransferase and aspartate aminotransferase levels 1 d after ablation than based line levels (P < 0.05) while the levels decreased close to pre-ablation levels 1 w after ablation (P > 0.05). Conclusion: The newly designed MWA system is safe and more efficient than a commonly used RFA system. However, further clinical studies are warranted.

Keywords

• |microwave ablation|radiofrequency ablation|liver|contrast-enhanced ultrasound|animal study