MAGNETOSTIMULATION IN MRI
MAGNETOSTIMULATION IN MRI
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DOI：
10.1002/mrm.1910330506
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发表时间：
1995-05-01
影响因子：
3.3
通讯作者：
SCHMITT, F
中科院分区：
文献类型：
--
作者：
IRNICH, W;SCHMITT, F
国家和国际机构正在积极讨论 MRI 磁场强度水平的适当安全规定。目前的限制通常以开关速率 dB/dt 表示，但其有效性还有待商榷。电刺激基本定律的应用在理论和实验基础上均已成熟。该定律的应用与麦克斯韦定律相结合，产生了一个非常简单的方程，我们称之为磁刺激基本定律。该定律具有强度-持续时间曲线的双曲线形式，并允许估计能够刺激神经和肌肉的磁通密度的最低可能值。计算证明，心脏兴奋的阈值远高于神经和肌肉刺激的阈值。我们和其他作者的实验结果证实了磁刺激导出定律的正确性。根据这些发现，应重新考虑拟议的安全限制。
In national and international bodies, there is active discussion of appropriate safety regulations of levels of magnetic field strength in MRI. Present limits are usually expressed in terms of the switching rate dB/dt, but the validity of this is open to debate. Application of the fundamental law of electrostimulation is well-established, both on theoretical and experimental grounds. Application of this law, in combination with Maxwell's law, yields a very simple equation that we call the fundamental law of magnetostimulation. This law has the hyperbolic form of a strength-duration curve and allows an estimation of the lowest possible value of the magnetic flux density capable of stimulating nerves and muscles. Calculations prove that the threshold for heart excitation is much higher than those for nerve and muscle stimulations. Experimental results from us and other authors confirm the correctness of the derived laws for magnetostimulation. In light of these findings, proposed safety limits should be reconsidered.