Transmission Line Model of an Implanted Insulated Cable for Magnetic Resonance Imaging Radiofrequency Hazard Evaluation
Transmission Line Model of an Implanted Insulated Cable for Magnetic Resonance Imaging Radiofrequency Hazard Evaluation
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用于磁共振成像射频危害评估的植入绝缘电缆的传输线模型
DOI：
10.1109/jerm.2018.2852303
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发表时间：
2018
影响因子：
--
通讯作者：
J. Felblinger
中科院分区：
文献类型：
--
作者：
Alexia Missoffe;J. Kabil;P. Vuissoz;J. Felblinger
本文表明，可以模拟的功率沉积在电极的植入绝缘电缆提交的射频场的1.5 T磁共振成像模态（64 MHz）与传输线模型。这提供了一种与通常使用的传递函数模型更相关的物理替代方案。通过有限差分模型和传输线参数的函数的传递函数的一个新的解析公式之间的模型的等价性。首先，通过全波数值模拟分析了用传输线模型模拟绝缘电缆的可能性。研究表明，传递函数模型中传输线模型的假设对于嵌入仿组织凝胶中的简单电缆是正确的，并且从该分析中提取的传输线参数与根据物理定律推导出的解析公式一致。传输线模型的预测进行了比较，首先实验和模拟数据的电缆传递函数，然后实验和模拟数据的谐振行为作为一个功能的电缆长度与不同的终端条件。测量和模拟的传递函数完全符合传输线模型的传播常数的解析表达式。从传递函数中提取的传输线模型允许我们预测具有不同终端条件的两个电缆的谐振行为。
This paper demonstrates that one can model the power deposited at the electrode of an implanted insulated cable submitted to the radiofrequency field of a 1.5 T magnetic resonance imaging modality (64 MHz) with a transmission line model. This offers an alternative that is more related to physics to the usually used transfer function model. The equivalence between the models is shown through a finite difference model and a new analytical formula for the transfer function as a function of transmission line parameters. First, the possibility of modeling an insulated cable with a transmission line model was analyzed through full-wave numerical simulations. The assumption of a transmission line model underlying the transfer function model was shown to be right for a simple cable embedded in tissue imitating gel, and the transmission line parameters extracted from this analysis were consistent with analytical formulas derived from the laws of physics. The transmission line model predictions were first compared to experimental and simulated data of the cable transfer function and then to experimental and simulated data of the resonant behavior as a function of length of cables with different termination conditions. The measured and simulated transfer functions fit perfectly a transmission line model with an analytical expression of the propagating constant. The transmission line model extracted from the transfer function allows us to predict the resonant behavior of two cables with different termination conditions.