3D modeling of the total electric field induced by transcranial magnetic stimulation using the boundary element method.
3D modeling of the total electric field induced by transcranial magnetic stimulation using the boundary element method.
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DOI：
10.1088/0031-9155/54/12/002
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发表时间：
2009-06-21
影响因子：
3.5
通讯作者：
Fox PT
中科院分区：
文献类型：
--
作者：
Salinas FS;Lancaster JL;Fox PT
经颅磁刺激 (TMS) 通过非侵入性外部施加磁场提供高度局部化的大脑刺激。这种无创、无痛的技术为研究人员和临床医生提供了一种能够刺激中枢和周围神经系统的独特工具。然而，尚未对 TMS 产生的宏观电场进行完整的分析。在本文中，我们使用边界元法 (BEM) 讨论了 TMS 期间表面电荷积累产生的二次电场的重要性。使用简单的头部几何形状开发 3D 模型，以便测试模型并将其与测量值进行比较。还研究了组织几何形状、尺寸和电导率的影响。最后，使用逼真形状的头部模型来评估多个表面对总电场的影响。二次电场对靠近每个组织层的区域影响最大。在整个头部，次级电场强度通常为初级电场强度的 20% 到 35%。次要电场的方向通常与主要电场相反；然而，对于某些位置，情况并非如此（即从高电导率组织到低电导率组织）。这些发现表明，真实形状的头部几何形状对于总电场的精确建模非常重要。
Transcranial magnetic stimulation (TMS) delivers highly localized brain stimulations via non-invasive externally applied magnetic fields. This non-invasive, painless technique provides researchers and clinicians with a unique tool capable of stimulating both the central and peripheral nervous systems. However, a complete analysis of the macroscopic electric fields produced by TMS has not yet been performed. In this paper, we addressed the importance of the secondary E-field created by surface charge accumulation during TMS using the boundary element method (BEM). 3D models were developed using simple head geometries in order to test the model and compare it with measured values. The effects of tissue geometry, size and conductivity were also investigated. Finally, a realistically shaped head model was used to assess the effect of multiple surfaces on the total E-field. Secondary E-fields have the greatest impact at areas in close proximity to each tissue layer. Throughout the head, the secondary E-field magnitudes typically range from 20% to 35% of the primary E-field's magnitude. The direction of the secondary E-field was generally in opposition to the primary E-field; however, for some locations, this was not the case (i.e. going from high to low conductivity tissues). These findings show that realistically shaped head geometries are important for accurate modeling of the total E-field.