Experimental

European Radiology

, Volume 16, Issue 8, pp 1826-1834

First online:

Evolving technology in bipolar perfused radiofrequency ablation: assessment of efficacy, predictability and safety in a pig liver model

  • Fernando BurdíoAffiliated withDepartment of Surgery A, Hospital Clínico Universitario Lozano BlesaDepartment of Surgery, University of Barcelona Email author 
  • , Ana NavarroAffiliated withDepartment of Surgery A, Hospital Clínico Universitario Lozano Blesa
  • , Ramón SousaAffiliated withDepartment of Surgery A, Hospital Clínico Universitario Lozano Blesa
  • , José M. BurdíoAffiliated withDepartment of Electric Engineering and Communications, University of Zaragoza
  • , Antonio GüemesAffiliated withDepartment of Surgery A, Hospital Clínico Universitario Lozano Blesa
  • , Ana GonzalezAffiliated withDepartment of Animal Pathology and Surgery, Veterinary Faculty, University of Zaragoza
  • , Ignacio CruzAffiliated withDepartment of Animal Pathology and Surgery, Veterinary Faculty, University of Zaragoza
  • , Tomás CastiellaAffiliated withDepartment of Pathology, Hospital Clínico Universitario Lozano Blesa
  • , Ricardo LozanoAffiliated withDepartment of Surgery A, Hospital Clínico Universitario Lozano Blesa
    • , Enrique BerjanoAffiliated withDepartment of Electronic Engineering, Polytechnic University of Valencia
    • , Joan FiguerasAffiliated withDepartment of Surgery, University of Barcelona
    • , Miguel A. de GregorioAffiliated withDepartment of Radiology, Hospital Clínico Universitario Lozano Blesa

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Abstract

Bipolar radiofrequency (RF) ablation, especially with perfusion of saline, has been shown to increase volume over monopolar conventional methods. The aims of this study are to study whether this method is linked to too flattened thermal lesions and premature rise of impedance and to elucidate some safety concerns. Eighteen RF ablations were performed using a 1.8-mm-diameter bipolar applicator in the liver of nine healthy pigs through laparotomy with or without temporary vascular occlusion [the Pringle maneuver (PGM)]: group A (n=9), without PGM; group B (n=9), with PGM. Hypertonic saline solutions (3% and 20 %) were injected through the applicator at a rate of 400 ml/h during the procedure. The pigs were followed up and they were euthanased on the 15th day. Impedance, current, power output, energy output, temperatures, diameters of thermal lesion, volume, sphericity ratio of thermal lesion were correlated among groups. Impedance at the end of the procedure (50.00 Ω±28.39 and 52.88 Ω±26.77, for groups A and B, respectively) was very similar to the starting impedance (50 Ω). In a median of 1 (range, 0–6) time per RF ablation procedure a reduction of 30 W from the selected power supply was observed during the RF ablation procedure linked to a slight increase of impedance. Volume and short diameter of thermal lesion were 21.28 cm3±11.78 and 2.85 cm±0.87 for group A, 87.51 cm3±25.20 and 4.31 cm±0.65 for group B. Continuous thermal between both electrodes were described with a global sphericity ratio of 1.91. One major complication (thermal injury to the stomach) was encountered in a case of cross-sectional necrosis of the targeted liver and attributed to heat diffusion after the procedure. This method has been shown to determine: (1) the relative control of impedance during the procedure; (2) ovoid and relatively large thermal lesions with less dependence upon closest vessels.

Keywords

Radiofrequency ablation Liver neoplasms Liver interventional procedures