使用专用多通道磁共振线圈对人类运动皮层进行高灵敏度经颅磁刺激/功能磁共振成像
High-sensitivity TMS/fMRI of the Human Motor Cortex Using a Dedicated Multichannel MR Coil.
作者信息
Navarro de Lara Lucia I, Tik Martin, Woletz Michael, Frass-Kriegl Roberta, Moser Ewald, Laistler Elmar, Windischberger Christian
机构信息
Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Währinger Guertel 18-20, A-1090 Wien, Vienna, Austria; MR Center of Excellence, Medical University of Vienna, Vienna, Austria.
Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Währinger Guertel 18-20, A-1090 Wien, Vienna, Austria; MR Center of Excellence, Medical University of Vienna, Vienna, Austria.
出版信息
Neuroimage. 2017 Apr 15;150:262-269. doi: 10.1016/j.neuroimage.2017.02.062. Epub 2017 Feb 22.
PURPOSE
To validate a novel setup for concurrent TMS/fMRI in the human motor cortex based on a dedicated, ultra-thin, multichannel receive MR coil positioned between scalp and TMS system providing greatly enhanced sensitivity compared to the standard birdcage coil setting.
METHODS
A combined TMS/fMRI design was applied over the primary motor cortex based on 1Hz stimulation with stimulation levels of 80%, 90%, 100%, and 110% of the individual active motor threshold, respectively. Due to the use of a multichannel receive coil we were able to use multiband-accelerated (MB=2) EPI sequences for the acquisition of functional images. Data were analysed with SPM12 and BOLD-weighted signal intensity time courses were extracted in each subject from two local maxima (individual functional finger tapping localiser, fixed MNI coordinate of the hand knob) next to the hand area of the primary motor cortex (M1) and from the global maximum.
RESULTS
We report excellent image quality without noticeable signal dropouts or image distortions. Parameter estimates in the three peak voxels showed monotonically ascending activation levels over increasing stimulation intensities. Across all subjects, mean BOLD signal changes for 80%, 90%, 100%, 110% of the individual active motor threshold were 0.43%, 0.63%, 1.01%, 2.01% next to the individual functional finger tapping maximum, 0.73%, 0.91%, 1.34%, 2.21% next to the MNI-defined hand knob and 0.88%, 1.09%, 1.65%, 2.77% for the global maximum, respectively.
CONCLUSION
Our results show that the new setup for concurrent TMS/fMRI experiments using a dedicated MR coil array allows for high-sensitivity fMRI particularly at the site of stimulation. Contrary to the standard birdcage approach, the results also demonstrate that the new coil can be successfully used for multiband-accelerated EPI acquisition. The gain in flexibility due to the new coil can be easily combined with neuronavigation within the MR scanner to allow for accurate targeting in TMS/fMRI experiments.
目的
验证一种用于人类运动皮层同步经颅磁刺激（TMS）/功能磁共振成像（fMRI）的新型装置，该装置基于一个专用的超薄多通道接收磁共振线圈，置于头皮和TMS系统之间，与标准鸟笼线圈设置相比，灵敏度大大提高。
方法
基于1Hz刺激，分别以个体主动运动阈值的80%、90%、100%和110%的刺激水平，对初级运动皮层应用联合TMS/fMRI设计。由于使用了多通道接收线圈，我们能够使用多频段加速（MB = 2）的回波平面成像（EPI）序列来采集功能图像。使用SPM12对数据进行分析，并在每个受试者中从初级运动皮层（M1）手部区域旁边的两个局部最大值（个体功能性手指轻敲定位器，手部旋钮的固定蒙特利尔神经研究所（MNI）坐标）以及全局最大值中提取血氧水平依赖（BOLD）加权信号强度时间历程。
结果
我们报告了出色的图像质量，没有明显的信号丢失或图像失真。在三个峰值体素中的参数估计显示，随着刺激强度的增加，激活水平呈单调上升。在所有受试者中，个体功能性手指轻敲最大值旁边，个体主动运动阈值的80%、90%、100%、110%对应的平均BOLD信号变化分别为0.43%、0.63%、1.01%、2.01%；在MNI定义的手部旋钮旁边分别为0.73%、0.91%、1.34%、2.21%；全局最大值对应的分别为0.88%、1.09%、1.65%、2.77%。
结论
我们的结果表明，使用专用磁共振线圈阵列的同步TMS/fMRI实验新装置尤其在刺激部位可实现高灵敏度fMRI。与标准鸟笼方法相反，结果还表明新线圈可成功用于多频段加速的EPI采集。新线圈带来的灵活性提升可轻松与磁共振扫描仪内的神经导航相结合，以便在TMS/fMRI实验中实现精确靶向。
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