title: Double radiofrequency ablation is more extensive with a spherical zone shape compared to single ablation in a pig liver model.
abstract: OBJECTIVE
  We compared the duration of ablation and the area of coagulation necrosis between a single ablation method (SAM) and a double ablation method (DAM) with a 'multitined expandable' electrode (LeVeen 2 cm) for radiofrequency ablation (RFA) using pig liver.
  
  
  METHODS
  In the SAM group, ablation was completed after the first roll-off. In the DAM group, an additional ablation was performed to achieve a second roll-off. The comparison was made of the time required for roll-off and the extent of coagulation necrosis between the both groups. The Ellipticity index (EI) quantitatively describes the shape of the general RF ablation zone in the axial plane.
  
  
  RESULTS
  There was no statistically significant difference in the interval until the first roll-off between both groups (SAM group: 100.7+/-24.7 seconds vs DAM group: 103.2+/-37.7 seconds, P=0.43). In the DAM group, the interval from the start of the additional ablation until the second roll-off was 154.0+/-86.9 seconds, longer than the interval for the first roll-off (P=0.023). The extent of coagulation necrosis was significantly more extensive in the DAM group (axial diameter, mean+/-SD, 26.2+/-2.8mm) x (maximal diameter: 29.3+/-1.6mm) x (minimal diameter: 26.5+/-3.6mm) compared to the SAM group with (23.0+/-3.3mm) x (23.7+/-3.1mm) x (20.0+/-2.5mm), respectively. Although there was no statistically significant difference in the EI between both groups, macroscopically, the shape of coagulation necrosis tended to be non-spherical in the SAM group and spherical in the DAM group.
  
  
  CONCLUSIONS
  The DAM with a 'multitined expandable' electrode was more extensive with a spherical zone shape compared to the SAM.
authors: Departments of Digestive and Cardiovascular Medicine, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima, Japan.
authors: Atsuo
authors: A
authors: Oshio
authors: Katsuyoshi
authors: K
authors: Tamaki
authors: Ichiro
authors: I
authors: Shimizu
authors: Hiroshi
authors: H
authors: Fukuno
authors: Mari
authors: M
authors: Urata
authors: Susumu
authors: S
authors: Ito
authors: Nobuya
authors: N
authors: Sano
mesh_terms: D000818:Animals; D017115:Catheter Ablation / Q000379:methods*; D008099:Liver / Q000601:surgery*; D008113:Liver Neoplasms / Q000601:surgery; D023421:Models, Animal; D013552:Swine; D013997:Time Factors