The discrepancy between human peripheral nerve chronaxie times as measured using magnetic and electric field stimuli: the relevance to MRI gradient coil safety.
The discrepancy between human peripheral nerve chronaxie times as measured using magnetic and electric field stimuli: the relevance to MRI gradient coil safety.
复制标题
使用磁场和电场刺激测量的人类周围神经计时时间之间的差异：与 MRI 梯度线圈安全性的相关性。
DOI：
10.1088/0031-9155/54/19/020
复制
发表时间：
2009
影响因子：
3.5
通讯作者：
Chronik,BlaineA
中科院分区：
文献类型：
--
作者：
Recoskie,BryanJ;Scholl,TimothyJ;Chronik,BlaineA
外周神经刺激(PNS)是由梯度线圈快速变化的磁场产生的电场引起的，是磁共振成像中关注的问题。暴露在电场或变化磁场中的神经有望表现出一致的阈值特征，这促使直接应用文献中的电场暴露标准来指导MRI梯度磁场暴露标准的发展。通过比较22名健康受试者的电磁PNS曲线的时间轴时间来检验电场和磁场暴露的一致性。分别使用表面电极和8字形磁线圈测量前臂暴露的电刺激阈值和磁刺激阈值。电场和磁场条件下的平均时轴时间分别为109±11微米S和651±53微米S(±SE)。我们并不认为这些结果质疑PNS的基本机制，即快速切换的梯度磁场在人体组织中感应电场，从而导致PNS。然而，这一结果确实促使我们建议，当使用文献中的电场暴露数据来设置MRI中的梯度线圈PNS安全标准时，必须特别注意。
Peripheral nerve stimulation (PNS) resulting from electric fields induced from the rapidly changing magnetic fields of gradient coils is a concern in MRI. Nerves exposed to either electric fields or changing magnetic fields would be expected to display consistent threshold characteristics, motivating the direct application of electric field exposure criteria from the literature to guide the development of gradient magnetic field exposure criteria for MRI. The consistency of electric and magnetic field exposures was tested by comparing chronaxie times for electric and magnetic PNS curves for 22 healthy human subjects. Electric and magnetic stimulation thresholds were measured for exposure of the forearm using both surface electrodes and a figure-eight magnetic coil, respectively. The average chronaxie times for the electric and magnetic field conditions were 109±11 µs and 651±53 µs (±SE), respectively. We do not propose that these results call into question the basic mechanism, namely that rapidly switched gradient magnetic fields induce electric fields in human tissues, resulting in PNS. However, this result does motivate us to suggest that special care must be taken when using electric field exposure data from the literature to set gradient coil PNS safety standards in MRI.