Purpose: To evaluate the efficacy of radiofrequency ablation (RFA) for a subdiaphragmatic lesion in the liver using cool-wet tip electrode that is a kind of perfusion electrode
Methods and Materials: A total of 35 subdiaphragmatic lesions in 33 patients were treated by RFA using cool-wet tip electrode ® (RF Medical, Seoul, Korea). The electrode with 2 cm (n=26) or 3 cm active tip (n=9) was chosen according to the lesion size. The approaching direction of an electrode was divided into vertical (2 cm tip, n=19; 3 cm tip, n=8) and parallel (2 cm tip, n=5; 3 cm tip, n=3) to the diaphragm. 200W generator (Valleylab, Burlington) was used. The volume and shape of the ablating zone was measured on portal phase of immediate enhanced CT.
Results: The mean volume (15.0 ml) of ablating zone with vertical approach (VA) was smaller than that (24.1ml) with parallel approach (PA). The mean volume of ablating zone by 2 cm and 3 cm active tip electrode with VA were 10.5 ml and 22.3 ml, respectively. And each of that with PA were 14.8 ml and 30.5 ml. Both of images with VA and PA showed frequently round shape (74.1% with 20 patients and 62.5% with 5 patients, respectively).
Conclusion: RFA of subdiaphragmatic hepatic lesion using cool-wet tip electrode seems to be a promising approach. RFA with PA frequently revealed round shaped RF zone rather than ovoid. PA had better efficiency in creating a larger ablation zone than does VA.