Chronik Blaine A, Ramachandran Meena
Department of Electrical Engineering, Stanford University, Stanford, California 94305, USA.
J Magn Reson Imaging. 2003 Jun;17(6):716-21. doi: 10.1002/jmri.10300.
To examine peripheral nerve stimulation (PNS) thresholds for normal human subjects in magnetic resonance imaging (MRI) gradient coils, and determine if observed thresholds could be predicted based on gross physiologic measurements.
PNS thresholds for 21 healthy normal subjects were measured using a whole-body gradient coil. Subjects were exposed to a trapezoidal echo-planar imaging (EPI) gradient waveform and the total change in gradient strength (DeltaG) required to cause PNS as a function of the duration of the gradient switching time (tau) were measured. Correlation coefficients and corresponding P values were calculated for the PNS threshold measurements against simple physiologic measurements taken of the subjects, including weight, height, girth, and average body fat percentage, in order to determine if there were any easily observable dependencies.
No convincing correlations between threshold parameters and gross physiologic measurements were observed.
These results suggest it is unlikely that a simple physiologic measurement of subject anatomy can be used to guide the operation of MRI scanners in a subject-specific manner in order to increase gradient system performance while avoiding PNS.
检测正常人类受试者在磁共振成像（MRI）梯度线圈中的外周神经刺激（PNS）阈值，并确定能否基于大体生理测量来预测观察到的阈值。
使用全身梯度线圈测量21名健康正常受试者的PNS阈值。受试者暴露于梯形回波平面成像（EPI）梯度波形下，测量引起PNS所需的梯度强度总变化（ΔG）作为梯度切换时间（τ）的函数。针对受试者的简单生理测量（包括体重、身高、腰围和平均体脂百分比）计算PNS阈值测量的相关系数和相应的P值，以确定是否存在任何易于观察到的相关性。
未观察到阈值参数与大体生理测量之间有令人信服的相关性。
这些结果表明，不太可能通过对受试者解剖结构进行简单的生理测量，以受试者特异性方式指导MRI扫描仪的操作，从而在避免PNS的同时提高梯度系统性能。
