title: Experimental radiofrequency ablation near the portal and the hepatic veins in pigs: differences in efficacy of a monopolar ablation system.
abstract: BACKGROUND
  We sought to compare the efficacy of a monopolar radiofrequency ablation system in vivo near the portal vein and the hepatic veins in porcine liver.
  
  
  METHODS
  Radiofrequency 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.
  
  
  RESULTS
  Volumes (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 <or= 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).
  
  
  CONCLUSIONS
  Higher 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.
authors: Department of Radiology, University of Cologne, Cologne, Germany. cbangard@gmx.de
authors: Christopher
authors: C
authors: Bangard
authors: Axel
authors: A
authors: Gossmann
authors: Hans U
authors: HU
authors: Kasper
authors: Martin
authors: M
authors: Hellmich
authors: Jürgen H
authors: JH
authors: Fischer
authors: Arnulf
authors: A
authors: Hölscher
authors: Klaus
authors: K
authors: Lackner
authors: Dirk L
authors: DL
authors: Stippel