Department of Research and Development, Kempenhaeghe, Sterkselseweg 65, 5591 VE Heeze, The Netherlands; Department of Physics and Medical Technology, VU University Medical Center, De Boelelaan 1118,1081 HZ Amsterdam, The Netherlands.
Department of Physics and Medical Technology, VU University Medical Center, De Boelelaan 1118,1081 HZ Amsterdam, The Netherlands.
Neuroimage. 2013 Jul 15;75:238-248. doi: 10.1016/j.neuroimage.2013.02.033. Epub 2013 Feb 26.
EEG-correlated functional MRI (EEG-fMRI) visualizes brain regions associated with interictal epileptiform discharges (IEDs). This technique images the epileptiform network, including multifocal, superficial and deeply situated cortical areas. To understand the role of EEG-fMRI in presurgical evaluation, its results should be validated relative to a gold standard. For that purpose, EEG-fMRI data were acquired for a heterogeneous group of surgical candidates (n=16) who were later implanted with subdural grids and strips (ECoG). The EEG-fMRI correlation patterns were systematically compared with brain areas involved in IEDs ECoG, using a semi-automatic analysis method, as well as to the seizure onset zone, resected area, and degree of seizure freedom. In each patient at least one of the EEG-fMRI areas was concordant with an interictally active ECoG area, always including the early onset area of IEDs in the ECoG data. This confirms that EEG-fMRI reflects a pattern of onset and propagation of epileptic activity. At group level, 76% of the BOLD regions that were covered with subdural grids, were concordant with interictally active ECoG electrodes. Due to limited spatial sampling, 51% of the BOLD regions were not covered with electrodes and could, therefore, not be validated. From an ECoG perspective it appeared that 29% of the interictally active ECoG regions were missed by EEG-fMRI and that 68% of the brain regions were correctly identified as inactive with EEG-fMRI. Furthermore, EEG-fMRI areas included the complete seizure onset zone in 83% and resected area in 93% of the data sets. No clear distinction was found between patients with a good or poor surgical outcome: in both patient groups, EEG-fMRI correlation patterns were found that were either focal or widespread. In conclusion, by comparison of EEG-fMRI with interictal invasive EEG over a relatively large patient population we were able to show that the EEG-fMRI correlation patterns are spatially accurate at the level of neurosurgical units (i.e. anatomical brain regions) and reflect the underlying network of IEDs. Therefore, we expect that EEG-fMRI can play an important role for the determination of the implantation strategy.
脑电相关功能磁共振成像（EEG-fMRI）可用于可视化与癫痫样放电（IEDs）相关的脑区。该技术可用于成像癫痫样网络，包括多灶性、表浅和深部皮质区。为了理解 EEG-fMRI 在术前评估中的作用，其结果应与金标准进行验证。为此，我们对一组接受手术的患者（n=16）进行了 EEG-fMRI 数据采集，这些患者随后被植入硬膜下网格和条带（ECoG）。采用半自动分析方法，系统比较了 EEG-fMRI 相关模式与 ECoG 记录的 IEDs 相关脑区，也与发作起始区、切除区和癫痫无发作程度进行了比较。在每位患者中，至少有一个 EEG-fMRI 区域与 IEDs 期 ECoG 活性区域相吻合，始终包括 ECoG 数据中 IEDs 的早期起始区。这证实了 EEG-fMRI 反映了癫痫活动的起始和传播模式。在组水平上，76%的覆盖有硬膜下网格的 BOLD 区域与 IEDs 期 ECoG 电极相吻合。由于空间采样有限，51%的 BOLD 区域未被电极覆盖，因此无法进行验证。从 ECoG 的角度来看，有 29%的 IEDs 期 ECoG 区域被 EEG-fMRI 漏诊，而 68%的脑区被 EEG-fMRI 正确识别为无活性。此外，在 83%的数据集中，EEG-fMRI 区域包括了完整的发作起始区，在 93%的数据集中包括了切除区。在手术预后良好或较差的患者之间，没有发现明显的区别：在两组患者中，都发现了 EEG-fMRI 相关模式，既有局灶性的，也有广泛性的。总之，通过对相对较大的患者群体进行 EEG-fMRI 与 IEDs 期的侵入性 EEG 比较，我们能够证明 EEG-fMRI 相关模式在神经外科单元（即解剖脑区）的空间定位上是准确的，并反映了 IEDs 的基础网络。因此，我们预计 EEG-fMRI 可以在确定植入策略方面发挥重要作用。
