title: Estimation of saline-mixed tissue conductivity and ablation lesion size.
abstract: In radiofrequency ablation (RFA), saline infusion is beneficial for enhancing electrical conductivity, which allows more energy dissipation into target tissue, resulting in increased lesion size. Computational simulation has been a popular method to estimate lesion size from RFA treatment, but it has not been used effectively for saline-infused RFA, for lack of methods to address the conductivity properties of saline-tissue mixtures. To fill this gap, we propose a microscopic mixture model to derive the effective temperature-dependent conductivities of a saline-tissue mixture. We modeled a small block of 6% hypertonic saline-infused liver tissue as a 1 × 1 × 1 cm cube, which was divided into 64-1000 elements, with each element representing either liver tissue or saline. A 1:1 mixing of saline and liver tissue was assumed to calculate the effective conductivities at 30, 50, 70, and 90°C. Different mixing conditions (2:1 and 1:2 of saline to liver tissue) were also tested to observe the effect of mixing ratio on the resulting data. Then, the derived conductivities were applied for 3D hypertonic saline-infused RFA simulation. The results matched our previous experimental measurements within 13%. The proposed model is customizable in constructing mixtures of multiple components, and can thus be expanded to include the effects of various anatomical microstructures and materials.
authors.affiliation: School of Mechanical Engineering, Chung-Ang University, Seoul 156-756, Republic of Korea.
authors.forename: Joong
authors.initials: J
authors.lastname: Yull Park
authors.forename: Chan
authors.initials: C
authors.lastname: Young Park
authors.forename: Jeong
authors.initials: J
authors.lastname: Min Lee
mesh_terms: D000818:Animals; D017115:Catheter Ablation / Q000379:methods*; D002417:Cattle; D003198:Computer Simulation; D004553:Electric Conductivity; D004566:Electrodes; D020342:Finite Element Analysis; D008099:Liver / Q000502:physiology / Q000601:surgery; D008113:Liver Neoplasms / Q000503:physiopathology* / Q000628:therapy*; D008954:Models, Biological; D012965:Sodium Chloride / Q000737:chemistry; D013696:Temperature
chemical_list: D012965:Sodium Chloride