Grouiller Frédéric, Jorge João, Pittau Francesca, van der Zwaag Wietske, Iannotti Giannina Rita, Michel Christoph Martin, Vulliémoz Serge, Vargas Maria Isabel, Lazeyras François
Department of Radiology and Medical Informatics, University of Geneva, Rue Gabrielle-Perret-Gentil 4, 1211, Geneva 14, Switzerland.
Laboratory for Functional and Metabolic Imaging, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
MAGMA. 2016 Jun;29(3):605-16. doi: 10.1007/s10334-016-0536-5. Epub 2016 Mar 5.
The aim of this study was to demonstrate that eloquent cortex and epileptic-related hemodynamic changes can be safely and reliably detected using simultaneous electroencephalography (EEG)-functional magnetic resonance imaging (fMRI) recordings at ultra-high field (UHF) for clinical evaluation of patients with epilepsy.
Simultaneous EEG-fMRI was acquired at 7 T using an optimized setup in nine patients with lesional epilepsy. According to the localization of the lesion, mapping of eloquent cortex (language and motor) was also performed in two patients.
Despite strong artifacts, efficient correction of intra-MRI EEG could be achieved with optimized artifact removal algorithms, allowing robust identification of interictal epileptiform discharges. Noise-sensitive topography-related analyses and electrical source localization were also performed successfully. Localization of epilepsy-related hemodynamic changes compatible with the lesion were detected in three patients and concordant with findings obtained at 3 T. Local loss of signal in specific regions, essentially due to B 1 inhomogeneities were found to depend on the geometric arrangement of EEG leads over the cap.
These results demonstrate that presurgical mapping of epileptic networks and eloquent cortex is both safe and feasible at UHF, with the benefits of greater spatial resolution and higher blood-oxygenation-level-dependent sensitivity compared with the more traditional field strength of 3 T.
本研究旨在证明，对于癫痫患者的临床评估，使用超高场（UHF）下的同步脑电图（EEG）-功能磁共振成像（fMRI）记录能够安全、可靠地检测出明确的皮质和癫痫相关的血流动力学变化。
在7T下，使用优化设置对9例患有病灶性癫痫的患者进行同步EEG-fMRI检查。根据病灶的定位，还对2例患者进行了明确皮质（语言和运动）的图谱绘制。
尽管存在强烈的伪影，但通过优化的伪影去除算法能够有效校正MRI内EEG，从而可靠地识别发作间期癫痫样放电。对噪声敏感的地形图相关分析和电源定位也成功进行。在3例患者中检测到与病灶相符的癫痫相关血流动力学变化的定位，且与在3T时获得的结果一致。发现特定区域的局部信号丢失主要归因于B1不均匀性，这取决于EEG导联在帽状电极上的几何排列。
这些结果表明，与更传统的3T场强相比，在UHF下进行癫痫网络和明确皮质的术前图谱绘制既安全又可行，具有更高的空间分辨率和更高的血氧水平依赖敏感性。
