Encephalographic MRI and Epilepsy Discharge Localization

描述(由申请人提供)：我们研究的首要目标是比使用标准技术所能达到的更直接地成像癫痫潜在的脑放电。癫痫患者通常在两次发作之间有异常的神经元放电，称为发作间期棘波。虽然它们的存在可以通过脑电检测到，但这些尖峰的来源仍然很难识别。我们正在开发一套新的成像工具和分析方法，以帮助我们通过这些放电对磁共振图像(脑电磁共振成像或EMRI)的影响来检测它们。该技术基于对脑电(EEG)和梯度回波平面磁共振图像的同时高速采集，并使用EEG信号来识别在电活动时期采集的图像。在一小部分癫痫患者中，我们在MR图像中显示出快速反应，几乎与EEG上看到的发作间期棘波同步。我们的目标是将EMRI扩展为一种具有临床实用价值的工具，用于精确定位癫痫样活动的病灶。我们的第一个具体目标是对伴有中央-颞叶棘波的良性癫痫(BECTS)的儿童患者进行成像，在这些患者中，棘波频繁且在解剖学上被精确定位。将研究发作间期棘波所涉及的区域的空间范围，以确定这是否与这组患者中存在神经精神或发育异常有关。我们的第二个具体目标是使用EMRI来评估一组难治性癫痫患者，在这些患者中，作为癫痫手术的第一步，侵入性皮质电极将被植入脑内。侵入性电极识别的区域将与EMRI识别的区域进行比较。最后，我们的第三个具体目标是系统地改变EMRI采集中使用的成像参数，并利用电流体模，以优化我们的方案，并阐明我们观察到的快速MR反应的机制。EMRI有可能改善术前定位，并将癫痫切除术转变为一期手术，避免了对长时间的颅内记录的需要。更广泛地说，这项技术可能会允许在个体患者中更有效地部署抗癫痫药物治疗，并通过直接展示对发作间期活动的治疗效果，提供测试新药物的手段。这项工作可能会加深我们对癫痫样放电及其扩散的病理生理学的理解。

DESCRIPTION (provided by applicant): The overarching aim of our research is to more directly image the cerebral discharges underlying epilepsy than has been achievable using standard techniques. Epilepsy patients often have abnormal neuronal discharges between seizures, called interictal spikes. Although their presence can be detected using EEG, the source of these spikes remains difficult to identify. We are developing a novel set of imaging tools and analysis methods to help us detect these discharges via their effect on MR images (encephalographic magnetic resonance imaging, or eMRI). The technique is based upon simultaneous high-speed acquisition of electroencephalography (EEG) and gradient-echo echo-planar MR images, with the EEG signal used to identify the images acquired during electrically active epochs. In a small cohort of patients with epilepsy, we have demonstrated fast responses in the MR images, nearly simultaneous with the interictal spikes seen on EEG. Our goals here are to extend eMRI as a tool with clinical utility for precise localization of the foci of epileptiform activity. Our first specific aim is to image pediatric patients with benign epilepsy with centrotemporal spikes (BECTS), in whom spikes are frequent and exquisitely well localized anatomically. The spatial extent of the regions involved by the interictal spikes will be studied, in order to determine if this correlates with the presence of neuropsychiatric or developmental abnormalities in this group of patients. Our second specific aim is to use eMRI to assess a cohort of patients with medically intractable epilepsy, in whom invasive cortical electrodes will be implanted intracranially as the first step in their epilepsy surgery. The regions identified by the invasive electrodes will be compared with the regions identified by eMRI. Finally, our third specific aim is to systematically vary the imaging parameters used in the eMRI acquisition, and make use of an electric current phantom, in order to optimize our protocol and to elucidate the mechanisms underlying the fast MR responses we have observed. eMRI has the potential to improve presurgical localization and to transform epilepsy resection into a one-stage surgical procedure, avoiding the need for prolonged intracranial recordings. More broadly, the technique would potentially allow for more efficacious deployment of antiepileptic medical therapy in the individual patient, as well as providing a means for testing novel agents, by directly demonstrating treatment effects on interictal activity. This work is likely to deepen our understanding of the pathophysiology of epileptiform discharges and their spread.