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

Objective: 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.