Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA.
J Magn Reson Imaging. 2010 Feb;31(2):475-81. doi: 10.1002/jmri.22037.
To assess safety of clinical MRI of the head in patients with implanted model 100, 102, and 103 vagus nerve stimulation (VNS) Therapy Systems (Cyberonics, Inc., Houston, TX) in 3.0 Tesla MRI (GE Healthcare, Milwaukee, WI).
The distributions of the radiofrequency B(1) (+)-field produced by the clinically used transmit/receive (T/R) head coil (Advanced Imaging Research Incorporated, Cleveland, OH) and body coil were measured in a head and shoulders phantom. These measurements were supplemented by temperature measurements on the lead tips and the implantable pulse generator (IPG) of the VNS devices in a head and torso phantom with the same two coils. Clinical 3T MRI head scans were then acquired under highly controlled conditions in a series of 17 patients implanted with VNS.
Phantom studies showed only weak B(1) (+) fields at the location of the VNS IPG and leads for MRI scans using the T/R head coil. The MRI-related heating on a VNS scanned in vitro at 3T was also found to be minimal (0.4-0.8 degrees C at the leads, negligible at the IPG). The patient MRI examinations were completed successfully without any adverse incidents. No patient reported any heating, discomfort, or any other unusual sensation.
Safe clinical MRI head scanning of patients with implanted VNS is shown to be feasible on a GE Signa Excite 3T MRI system using one specific T/R head coil. These results apply to this particular MRI system configuration. Extrapolation or generalization of these results to more general or less controlled imaging situations without supporting data of safety is highly discouraged.
评估植入式 100、102 和 103 型迷走神经刺激（VNS）治疗系统（Cyberonics，Inc.，休斯顿，TX）的患者在 3.0T MRI（GE Healthcare，密尔沃基，WI）中进行临床头部 MRI 的安全性。
在头部和肩部体模中测量了临床使用的发射/接收（T/R）头线圈（Advanced Imaging Research Incorporated，克利夫兰，OH）和体线圈产生的射频 B（1）（+）场的分布。这些测量结果通过在具有相同两个线圈的头部和躯干体模中对 VNS 设备的导联尖端和可植入脉冲发生器（IPG）进行温度测量得到补充。然后，在一系列植入 VNS 的 17 名患者中，在高度受控的条件下进行了临床 3T MRI 头部扫描。
体模研究表明，在使用 T/R 头线圈进行 MRI 扫描时，VNS IPG 和导联的位置仅存在较弱的 B（1）（+）场。在 3T 体外扫描时，VNS 相关的加热也被发现非常低（导联处为 0.4-0.8°C，IPG 处可忽略不计）。患者 MRI 检查成功完成，没有任何不良事件。没有患者报告任何发热、不适或其他异常感觉。
在使用特定的 T/R 头线圈的 GE Signa Excite 3T MRI 系统上，对植入 VNS 的患者进行安全的临床头部 MRI 扫描是可行的。这些结果适用于特定的 MRI 系统配置。没有安全性支持数据的情况下，将这些结果推广或推广到更一般或控制较差的成像情况是非常不可取的。
