EX-VIVO EXPERIMENT ON RADIOFREQUENCY LIVER ABLATION WITH SALINE INFUSION THROUGH A SCREW-TIP CANNULATED ELECTRODE

Purpose: To investigate whether radiofrequency (RF) therapy with hyper tonic saline infusion through a hollow screw-tip electrode can cause a lesion size suitable for liver tumor ablation. Materials and methods: RF tissue ablation of 180 sites was performed by using a hollow screw -tip electrode in 40 freshly excised swine livers. Under both power an d temperature control modes, the ablation effects with and without var ious regimes of 5% hypertonic saline (1 ml/min) prior to and/or during the procedure were compared by measuring the size of lesions at disse ction and confirmed by T1 and T2 weighted magnetic resonance (MR) imag ing. Results: The maximal lesion diameter of 5.5 cm was reached at 30 W with saline infusion 1 min prior to and during 12 min of ablation. T he smaller sizes (P < 0.01) between 0.3 and 2.5 cm in diameter were me t with noninfusion or preinfusion-only groups. The RF ablation lesions appeared as hyper-and hypointense areas on T1 and T2 MR images, respe ctively. Conclusions: RF ablation in combination with present hollow s crew-tip electrode and saline infusion allows for necrotic development of suitable size for liver tumor ablation. Such ablated lesions can b e visualized with MR imaging. (C) 1997 Academic Press.