SALINE-ENHANCED RADIOFREQUENCY TISSUE ABLATION IN THE TREATMENT OF LIVER METASTASES

PURPOSE: To assess the effect of intraparenchymal saline injection on the results of radio-frequency (RF) tissue ablation. MATERIALS AND MET HODS: Ex vivo and in vivo animal RF ablation was performed with and wi thout intraparenchymal saline injection. Initially, saline was injecte d as a bolus (1-20 mi) before RF application. For subsequent in vivo s tudies, saline was injected as a bolus before RF application or contin uously (1 mL/min) during RF application. Finally, 14 patients with liv er metastases and one patient with primary cholangiocarcinoma were tre ated with the continuous infusion technique. A single RF electrode (ti p exposure, 1-3 cm) was used with various ablation parameters. RESULTS : With pretreatment bolus injection of saline, lesions measured 1.4 cm +/- 0.1, 1.6 cm +/- 0.2, and 1.2 cm +/- 0.1 in ex vivo liver, in vivo animal muscle, and in vivo animal liver, respectively. Without saline enhancement, lesion sizes were 1.0 +/- 0.2, 1.2 +/- 0.3 and 0.8 +/- 0 .1 cm, respectively. With continuous saline injection in in vivo pig l iver, lesion size was 1.8-4.1 cm in diameter. In human tumors, necrosi s volume was variable, but complete necrosis was seen in 13 of 25 lesi ons (diameter, 1.2-3.9 cm). Partial necrosis greater than 50% was seen in 12 lesions (diameter, 1.5-4.5 cm). CONCLUSION: Saline-enhanced RF ablation might permit percutaneous destruction of large liver lesions.