With or without spikes: localization of focal epileptic activity by simultaneous electroencephalography and functional magnetic resonance imaging
With or without spikes: localization of focal epileptic activity by simultaneous electroencephalography and functional magnetic resonance imaging
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DOI：
10.1093/brain/awr156
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发表时间：
2011-10-01
期刊：
影响因子：
14.5
通讯作者：
Vulliemoz, Serge
中科院分区：
文献类型：
--
作者：
Grouiller, Frederic;Thornton, Rachel C.;Vulliemoz, Serge
在药物难治性局灶性癫痫患者中，适合进行癫痫手术的患者，一致的非侵入性神经成像数据有助于指导有创性脑电记录或手术切除。同时的脑电和功能磁共振成像记录可以揭示与癫痫活动相关的血液动力学波动区域，并帮助定位其产生者。然而，这些研究中的许多(40%-70%)仍然不确定，主要是由于在同时记录过程中没有发作间期癫痫样放电，或者缺乏与发作间期癫痫样放电相关的血流动力学变化。我们研究了头皮脑电图上癫痫特异性电压图的存在是否与血流动力学变化相关，并有助于定位癫痫灶。在23例局灶性癫痫患者中，我们利用在扫描仪外进行长期临床监测时记录的平均发作间期癫痫样放电建立了癫痫特异性脑电地形图，并计算了该地形图与扫描仪内每个时间段的脑电记录的相关性。这个相关系数的时间进程被用作功能磁共振成像分析的回归变量，以绘制与这些癫痫特异性地图相关的血流动力学变化(与地形图相关的血流动力学变化)。该方法首先在5名在常规分析中与发作间期癫痫样放电相关的显著血流动力学改变的患者中得到验证。然后，我们将该方法应用于18名患者，这些患者由于没有发作间期癫痫样放电或没有明显的相关血流动力学变化，而同时进行了脑电和功能磁共振成像研究，结果不确定。对术后无癫痫发作的患者的结果与随后的脑电图和/或切除面积的一致性进行评估。在验证组中，与电压图相关的血流动力学变化与5/5患者的常规分析结果相似。在14/18名患者(78%)中，即使在同步记录期间没有检测到发作间期癫痫样放电，与癫痫活动相关的头皮地形图也与血流动力学相关。与电压图相关的血流动力学改变与颅内脑电或切除区域在空间上一致。我们发现，与内侧/极地颞叶癫痫相比，外侧颞叶和颞叶外新皮质癫痫患者的一致性更好，这可能是因为外侧颞叶和颞叶外癫痫活动的脑电电压图与生理活动图更不相似。我们的方法显著提高了同步脑电和功能磁共振成像的产量，以非侵入性地定位癫痫灶，使手术切除或植入颅内电极阵列具有更好的靶向性。
In patients with medically refractory focal epilepsy who are candidates for epilepsy surgery, concordant non-invasive neuroimaging data are useful to guide invasive electroencephalographic recordings or surgical resection. Simultaneous electroencephalography and functional magnetic resonance imaging recordings can reveal regions of haemodynamic fluctuations related to epileptic activity and help localize its generators. However, many of these studies (40-70%) remain inconclusive, principally due to the absence of interictal epileptiform discharges during simultaneous recordings, or lack of haemodynamic changes correlated to interictal epileptiform discharges. We investigated whether the presence of epilepsy-specific voltage maps on scalp electroencephalography correlated with haemodynamic changes and could help localize the epileptic focus. In 23 patients with focal epilepsy, we built epilepsy-specific electroencephalographic voltage maps using averaged interictal epileptiform discharges recorded during long-term clinical monitoring outside the scanner and computed the correlation of this map with the electroencephalographic recordings in the scanner for each time frame. The time course of this correlation coefficient was used as a regressor for functional magnetic resonance imaging analysis to map haemodynamic changes related to these epilepsy-specific maps (topography-related haemodynamic changes). The method was first validated in five patients with significant haemodynamic changes correlated to interictal epileptiform discharges on conventional analysis. We then applied the method to 18 patients who had inconclusive simultaneous electroencephalography and functional magnetic resonance imaging studies due to the absence of interictal epileptiform discharges or absence of significant correlated haemodynamic changes. The concordance of the results with subsequent intracranial electroencephalography and/or resection area in patients who were seizure free after surgery was assessed. In the validation group, haemodynamic changes correlated to voltage maps were similar to those obtained with conventional analysis in 5/5 patients. In 14/18 patients (78%) with previously inconclusive studies, scalp maps related to epileptic activity had haemodynamic correlates even when no interictal epileptiform discharges were detected during simultaneous recordings. Haemodynamic changes correlated to voltage maps were spatially concordant with intracranial electroencephalography or with the resection area. We found better concordance in patients with lateral temporal and extratemporal neocortical epilepsy compared to medial/polar temporal lobe epilepsy, probably due to the fact that electroencephalographic voltage maps specific to lateral temporal and extratemporal epileptic activity are more dissimilar to maps of physiological activity. Our approach significantly increases the yield of simultaneous electroencephalography and functional magnetic resonance imaging to localize the epileptic focus non-invasively, allowing better targeting for surgical resection or implantation of intracranial electrode arrays.