Hepatic radiofrequency ablation: in vivo and ex vivo comparisons of 15-gauge (G) and 17-G internally cooled electrodes

Objective: To compare the performance of the 15-G internally cooled electrode with that of the conventional 17-G internally cooled electrode. Methods: A total of 40 (20 for each electrode) and 20 ablation zones (10 for each electrode) were made in extracted bovine livers and in in vivo porcine livers, respectively. Technical parameters, three dimensions [long-axis diameter (Dl), vertical-axis diameter (Dv) and short-axis diameter (Ds)], volume and the circularity (Ds/Dl) of the ablation zone were compared. Results: The total delivered energy was higher in the 15-G group than in the 17-G group in both ex vivo and in vivo studies (8.78 +/- 1.06 vs 7.70 +/- 0.98 kcal, p=0.033; 11.20 +/- 1.13 vs 8.49 +/- 0.35 kcal, p=0.001, respectively). The three dimensions of the ablation zone had a tendency to be larger in the 15-G group than in the 17-G group in both studies. The ablation volume was larger in the 15-G group than in the 17-G group in both ex vivo and in vivo studies (29.61 +/- 7.10 vs 23.86 +/- 3.82 cm(3), p=0.015; 10.26 +/- 2.28 vs 7.79 +/- 1.68 cm(3), p=0.028, respectively). The circularity of ablation zone was not significantly different in both the studies. Conclusion: The size of ablation zone was larger in the 15-G internally cooled electrode than in the 17-G electrode in both ex vivo and in vivo studies. Advances in knowledge: Radiofrequency ablation of hepatic tumours using 15-G electrode is useful to create larger ablation zones.