Electrical and Thermal Analyses of Catheter-Based Irreversible Electroporation of Digestive Tract

Introduction Irreversible electroporation (IRE) combined with a catheter-based electrode during endoscopy is a potential alternative treatment method for digestive tract tumors. The aim of this study was to investigate the electrical and thermal injury to the digestive tract via numerical analyses and to evaluate the role and impact of electrode configurations and pulse settings on the efficacy and outcomes of IRE. Materials and Methods A finite element method was used to solve the numerical model. A digestive tract model having 4-mm-thick walls and two catheter-based electrode configuration models were constructed. The distributions of electric fields, temperature, electrical conductivity, tissue injury, and limitation on the pulse number required for IRE were calculated and compared. Results Electrode length is an important geometric parameter for electrodes in the monopolar model, while electrode spacing affects the outcomes in the bipolar model. Increasing the pulse voltage reduces the pulse number required for tissue ablation, while increasing the risk of thermal injury. In total, there were six NT-IRE protocols, twelve thermal-IRE protocols, and thrity thermal injury protocols. All of the NT-IRE protocols were set in bipolar models with a voltage of 0.50 kV. With increasing electrode spacing, the minimum pulse number decreased. However, thermal effects were inevitable in the monopolar model. Conclusions The electrode configuration and pulse settings are adjusted to achieve NT-IRE synergistically. The bipolar model is more reliable for achieving NT-IRE in 4-mm-thick digestive wall. Future in vitro and in vivo studies are needed to support and validate this conclusion.

引言 内镜操作中联合导管式电极的不可逆电穿孔（Irreversible Electroporation, IRE）技术，是消化道肿瘤的潜在替代治疗手段。本研究旨在通过数值分析手段，探究消化道的电损伤与热损伤情况，并评估电极构型与脉冲参数设置对IRE治疗效果及临床转归的作用与影响。材料与方法 本研究采用有限元法求解数值模型，构建了壁厚4 mm的消化道模型与两种导管电极构型模型。随后计算并对比了电场分布、温度场分布、电导率、组织损伤情况，以及IRE治疗所需脉冲数的限制条件。结果 单极模型中，电极长度为关键几何参数；双极模型中，电极间距则会影响治疗结局。提升脉冲电压可降低组织消融所需的脉冲数，但同时会增加热损伤风险。本研究共设置6种非热不可逆电穿孔（Non-thermal Irreversible Electroporation, NT-IRE）方案、12种热损伤IRE方案，以及30种热损伤相关方案。所有NT-IRE方案均采用双极模型，电压设定为0.50 kV。随着电极间距增大，所需最小脉冲数随之降低，但单极模型不可避免会产生热效应。结论 可通过协同调整电极构型与脉冲参数，实现非热不可逆电穿孔治疗。相较于单极模型，双极模型在壁厚4 mm的消化道组织中实现NT-IRE的可靠性更高。未来需开展体外与体内研究，以验证并支撑本研究结论。