基于真实解剖模型的心脏导管射频消融有限元仿真

Finite Element Modeling Simulation of Cardiac Radiofrequency Catheter Ablation Based on Heart Chamber Anatomy

利用有限元方法对心脏导管射频消融过程进行仿真,并对消融区的温度分布和损伤尺寸进行估算是当前研究的热点。目前绝大多数研究都集中在对简单模型的仿真,没有考虑到真实心脏的解剖结构,然而消融的结果与射频电极插入处的心脏形状密切相关。为研究心脏解剖结构对消融结果的影响,本研究提出利用真实病人的CT心脏数据进行有限元分析。首先,利用获取到的心脏内壁的结构网格,构建更接近真实环境的模型,同时支持电极插入位置和接触模式的任意设置。然后,通过Matlab调用COMSOL脚本语言进行生物热传导的有限元仿真分析,采用Pennes热力学方程并使用50℃作为损伤界定标准,获得消融区的温度分布和损伤尺寸的仿真结果。仿真结果发现:由于心脏结构的不规则导致损伤区域的轮廓并不完全对称,消融损伤区域的尺寸随着电极偏转角度和深度的变化而不同,其大小与电极偏转角度和插入深度正相关。这些发现表明,本研究所提出的方法可根据心脏结构估算特异性的损伤结果。

Finite element modeling （FEM） method has been utilized as a numerical tool to determine the temperature distribution and lesion size in studies of cardiac radiofrequency （RF） catheter ablation. However, most ablation models are very simple and none of the-previous FEM analyses take heart chamber anatomy into account. In this paper, a novel method was proposed to perform FEM analysis based on cardiac CT data. A detailed cardiac ablation model was created based on CT heart inner surface mesh, and various electrode positions were specified by user selection. Then COMSOL scripts were called by Matlab to perform FEM analysis. Pennes heat transfer equation was adopted and 50 ℃ was set as criteria for lesion size determination. The temperature profile and ablation lesion size were estimated. The simulation results revealed that the ablation lesion region shape was not totally symmetric due to the asymmetric heart chamber surface and varied with electrode insertion angles and penetration depths. Lesion region size had a positive correlation with angles and depths. The proposed method can achieve specified ablation result based on heart anatomy.