Safety and effect on ablation size of hydrochloric acid-perfused radiofrequency ablation in animal livers.

PURPOSE: Our objective was to determine the safety and ablation size of hydrochloric acid-perfused radiofrequency ablation (HCl-RFA) in liver tissues, prospectively using in vivo rabbit and ex vivo porcine liver models. MATERIALS AND METHODS: The livers in 30 rabbits were treated in vivo with perfusions of normal saline (controls) and HCl concentrations of 5%, 10%, 15%, and 20%, during RFA at 103 °C and 30 W for 3 min. For each experimental setting, six ablations were created. Safety was assessed by comparing baseline weight and selected laboratory values with those at 2, 7, and 14 days' post-ablation, and by histopathological analysis. The livers in 25 pigs were treated ex vivo with the same five perfusions during RFA at 103 °C, at both 30 W and 60 W, for 30 min. Ablation diameters and volumes were measured by two examiners. RESULTS: Rabbit weights and selected laboratory values did not differ significantly from baseline to 7 and 14 days' post-ablation, liver tissues outside the ablation zones were normal histologically, and adjacent organs showed no macroscopic damage. The mean ablation volumes in the porcine livers treated with HCl-RFA were all larger than those treated with normal saline perfusion during RFA (NS-RFA), at both 30 W and 60 W (p < 0.001). The largest ablation volume and transverse diameter were observed in the porcine livers during 10% HCl-RFA at 60 W, measuring 179.22 (SD = 24.79) cm3 and 6.84 (SD = 0.36) cm, respectively. CONCLUSIONS: Based on our experiments, HCl-RFA in the liver appears to be as safe as NS-RFA while also resulting in larger ablation zones.

Sequential and Simultaneous 4-Antenna Microwave Ablation in an Ex Vivo Bovine Liver Model.

AIMS: To determine the sizes and shapes of ablation zones in 4-antenna microwave ablation in ex vivo bovine liver model under different conditions of power delivery patterns, antenna spacings, and ablation durations, for further using of multi-antenna MWA strategies in the treatment of large hepatocellular carcinoma. METHODS: We tested protocols of eight ablations each on ex vivo bovine livers, involving simultaneous or sequential activation of four microwave antennas, spaced either 3 cm, 4 cm, or 5 cm apart, for either 10 or 15 min, at 60-W power. We determined the diameters, shapes, and temperatures of the ablation zones. RESULTS: Compared to sequential power delivery, simultaneous power delivery resulted in significantly larger ablation zone diameters (P < .001). The temperatures in ablation zones were significantly higher for simultaneous than for sequential power delivery. The largest ablation diameter (7.45 ± 0.06 cm) resulted from simultaneous delivery for 15 min using 4-cm antenna spacing. CONCLUSIONS: Simultaneous 4-antenna microwave ablation results in larger ablation zones than sequential ablation, and 4-cm antenna spacing with a 15-minute ablation duration creates the largest ablation zone. This information may provide multi-antenna MWA strategies for large HCC in the further clinical practice.