Department of Neurology, Vinzenz Von Paul Hospital, Rottweil, Germany.
Department Radiology, Medical Physics, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany.
Brain Topogr. 2021 May;34(3):373-383. doi: 10.1007/s10548-021-00832-6. Epub 2021 Mar 17.
EEG-fMRI has gained increasing importance in epilepsy pre-surgical diagnosis. However, 40-70% of EEG-fMRI recordings in patients lack interictal epileptiform discharges (IEDs) during the scan, which could be overcome by detecting matching topography maps. We tried to validate this method in clinical settings taking various electroclinical factors into consideration. Eleven patients who had undergone EEG-fMRI during pre-surgical evaluation for drug-resistant epilepsy and who had had clinical long-term video-EEG were studied. Spike-related blood oxygen level-dependent (BOLD) maps were created using IEDs occurring during the EEG-fMRI scan. Separate maps were then generated from IEDs marked on the clinical long-term EEG recordings, which were averaged to produce topographical IED maps and correlated with the EEGs recorded inside the scanner yielding a correlation coefficient time course. Epileptogenic zones were defined by an expert panel during pre-surgical evaluation and validated by an epilepsy surgery resulting in a good outcome. Both techniques' performance was evaluated according to factors including arousal during IED recording, IED topography and lateralization, lesion type, and localization. Topography-related EEG-fMRI yielded more specific results compared to the spike-related method. Superficial lesion location and ipsilateral IED seem to result in a higher concordance of BOLD maps. The polarity of BOLD responses may be lesion-dependent, and both positive and negative BOLD changes may be associated with the irritative zone. Topography-related EEG-fMRI may show improved specificity especially for superficial lesions producing ipsilateral spikes. This method can be used as an alternative either in the absence of spikes during the simultaneous EEG-fMRI acquisition or to sharpen a diffusely activated BOLD-map.
脑电图-fMRI 在癫痫术前诊断中越来越重要。然而，40-70%的癫痫患者在扫描过程中缺乏癫痫样放电（IEDs），这可以通过检测匹配的地形图来克服。我们考虑了各种临床电生理因素，试图在临床环境中验证这种方法。研究了 11 名在药物难治性癫痫术前评估中进行了脑电图-fMRI 检查并进行了临床长期视频脑电图检查的患者。使用脑电图-fMRI 扫描过程中发生的 IEDs 创建与棘波相关的血氧水平依赖（BOLD）图。然后从临床长期脑电图记录中标记的 IED 生成单独的地图，对其进行平均以产生地形图 IED 地图，并与扫描仪内记录的脑电图相关联，产生相关系数时间过程。在术前评估期间，由专家组定义致痫区，并通过导致良好结果的癫痫手术进行验证。根据包括 IED 记录期间觉醒、IED 形态和侧化、病变类型和定位在内的因素评估这两种技术的性能。与与棘波相关的方法相比，与形态相关的脑电图-fMRI 产生了更具体的结果。表面病变位置和同侧 IED 似乎导致 BOLD 地图的一致性更高。BOLD 反应的极性可能与病变有关，正性和负性 BOLD 变化都可能与兴奋区有关。与形态相关的脑电图-fMRI 可能具有更高的特异性，尤其是对于产生同侧棘波的浅表病变。这种方法可以作为替代方法，用于在同时进行的脑电图-fMRI 采集期间没有棘波的情况，或者用于锐化弥漫性激活的 BOLD 图。
