Experimental Radiofrequency Ablation Near the Portal and the Hepatic Veins in Pigs: Differences in Efficacy of a Monopolar Ablation System 1

BackgroundWe sought to compare the efficacy of a monopolar radiofrequency ablation system in vivo near the portal vein and the hepatic veins in porcine liver.Materials and methodsRadiofrequency ablation of healthy livers near the portal vein and the hepatic veins was performed in 10 pigs with a multitined expandable electrode. Volumes and diameters of zones of ablation were assessed by magnetic resonance imaging.ResultsVolumes (16.0 ± 5.5 mL, P = 0.001) and diameters (4.0 ± 0.7 cm, 3.3 ± 0.7 cm, 3.0 ± 0.6 cm, P ≤ 0.05) of the zones of ablation near the hepatic veins were larger than that near the portal vein (7.5 ± 4.1 mL, 3.2 ± 0.7 cm, 2.6 ± 0.7 cm, 2.4 ± 0.6 cm). Energy deposition needed to ablate liver tissue was higher (P = 0.003) for radiofrequency ablation near the portal vein (3.16 ± 1.58 kJ/mL) than for radiofrequency ablation near the hepatic veins (1.65 ± 1.14 kJ/mL).ConclusionsHigher energy deposition is needed to ablate liver tissue near the portal vein than near the hepatic veins. As a result, the zone of ablation is larger near the hepatic vein than near the portal vein.