Department of Electrical Energy, Systems and Automation, Ghent University, Ghent 9000, Belgium.
IEEE Trans Biomed Eng. 2011 Feb;58(2):310-20. doi: 10.1109/TBME.2010.2087758. Epub 2010 Oct 18.
In many important bioelectromagnetic problem settings, eddy-current simulations are required. Examples are the reduction of eddy-current artifacts in magnetic resonance imaging and techniques, whereby the eddy currents interact with the biological system, like the alteration of the neurophysiology due to transcranial magnetic stimulation (TMS). TMS has become an important tool for the diagnosis and treatment of neurological diseases and psychiatric disorders. A widely applied method for simulating the eddy currents is the impedance method (IM). However, this method has to contend with an ill conditioned problem and consequently a long convergence time. When dealing with optimal design problems and sensitivity control, the convergence rate becomes even more crucial since the eddy-current solver needs to be evaluated in an iterative loop. Therefore, we introduce an independent IM (IIM), which improves the conditionality and speeds up the numerical convergence. This paper shows how IIM is based on IM and what are the advantages. Moreover, the method is applied to the efficient simulation of TMS. The proposed IIM achieves superior convergence properties with high time efficiency, compared to the traditional IM and is therefore a useful tool for accurate and fast TMS simulations.
在许多重要的生物电磁问题中，需要进行涡流模拟。例如，在磁共振成像中减少涡流伪影的技术，以及涡流与生物系统相互作用的技术，如颅磁刺激（TMS）引起的神经生理学改变。TMS 已成为诊断和治疗神经疾病和精神障碍的重要工具。模拟涡流的一种广泛应用的方法是阻抗法（IM）。然而，该方法必须应对病态问题，因此收敛时间较长。在处理最优设计问题和灵敏度控制时，收敛速度变得更加关键，因为需要在迭代循环中评估涡流求解器。因此，我们引入了一种独立的 IM（IIM），它可以改善条件并加快数值收敛。本文展示了 IIM 是如何基于 IM 并具有哪些优势的。此外，该方法还应用于 TMS 的高效模拟。与传统的 IM 相比，所提出的 IIM 具有优越的收敛特性和高效率，因此是进行准确快速 TMS 模拟的有用工具。
