Fluid modulated radiofrequency ablation : an ex-vivo study in porcine liver

• Flüssigkeitsmodulierte Radiofrequenzablation : Ex-vivo-Versuche in Schweineleber

Müller, Halina; Mahnken, Andreas H. (Thesis advisor)

Aachen : Publikationsserver der RWTH Aachen University (2012)
Dissertation / PhD Thesis

Aachen, Techn. Hochsch., Diss., 2012

Abstract

The aim of this study was to investigate how the injection of conductive fluids into tissue before RFA, would affect to ablation process. The hypothesis being, that fluids with a high conductivity should enhance tissue conductivity and should therefore increase energy input into the tissue, achieving larger coagulation volumes. The fluids used in this study were: 0.9% Nacl solution, Magnevist®, Telebrix Gastro®, HAES, 5% glucose solution, 95% ethanol and distilled water. Bipolar RFA was carried out on freshly excised porcine liver specimen using a CelonLabPower RF-system and the internally cooled CelonProSurge T20 applicator. Before each ablation process, 1 ml of the fluid to be tested was injected into the specimen using a G21 hypothermic needle. Temperature within the specimen was recorded by inserting two fiberoptic thermocouples parallel to the applicator. Data concerning impedance, resistance and energy input was recorded using the CelonPower Monitor software. After RFA was completed, the specimens were dissected and the lesion size was assessed macroscopically using a ruler. Compared to RFA alone (mean coagulation size 1.42 cm3), significantly larger coagulations (p < 0.001) were achieved using HAES, glucose, Magnevist, TelebrixGastro® and Ethanol. The largest coagulation volumes were achieved with HAES, with a mean volume of 4.83 cm3, the smallest were achieved using RFA alone with a mean volume of 1.42 cm3. The highest energy input was achieved using ethanol with a mean energy input of 6.38 kJ and the longest time of energy application was achieved using 5% glucose solution with a mean heating time of 841.40 sec. Unexpected results were achieved using non-conductive fluids such as glucose solution or distilled water, indicating that the use of any fluid, irrelevant of its conductivity, seems to have an enhancing effect on RFA. This study on fluid-modulated RFA indicates that the injection of conductive fluids can increase the size of coagulation necrosis and energy input, by improving not only electrical conductivity, but possibly also thermal conductivity.

Institutions

• [811001-1]