Radiofrequency Ablation of Liver Tumors: How to Enlarge the Necrotic Zones?

In an attempt to increase necrotic zones in liver tissue by radiofrequency ablation fresh bovine liver was coagulated by means of a needle electrode continuously perfused with NaCl solution. Power output (60 W) and application time (15 min) were kept constant while the perfusion was varied in terms of saline concentration (0.9, 5.85 and 10%) and perfusion rate (40 or 80 ml/h). Our results showed that the use of higher osmolar saline solutions in radiofrequency ablation with perfused needle electrodes did not lead to significantly larger coagulation volumes. By contrast, increasing the perfusion rate produced significantly larger necrotic zones. Doubling the perfusion rate made it possible to reach higher temperatures (>60°C) within significantly shorter time.