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更直接地成像癫痫潜在的脑放电。癫痫患者通常在癫痫发作之间有异常的神经元放电，称为间歇峰。虽然它们的存在可以通过脑电图检测到，但这些尖峰的来源仍然难以确定。我们正在开发一套新的成像工具和分析方法，以帮助我们通过对MR图像（脑磁共振成像，或eMRI）的影响来检测这些放电。该技术基于同时高速采集脑电图（EEG）和梯度回波平面MR图像，脑电图信号用于识别在电活动时期获取的图像。在一个小的癫痫患者队列中，我们已经在MR图像中证明了快速反应，几乎与脑电图上看到的间歇尖峰同时出现。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成像儿童良性癫痫患者与中央颞叶尖峰（BECTS），其中尖峰是频繁和精细定位的解剖。为了确定这组患者是否存在神经精神或发育异常，将研究间隔尖峰所涉及的区域的空间范围。我们的第二个具体目标是使用eMRI来评估一组医学上难治性癫痫患者，在他们的癫痫手术中，侵入性皮质电极将被植入颅内。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，并利用电流幻象，以优化我们的方案并阐明我们观察到的快速MR响应的机制。eMRI有潜力改善术前定位，并将癫痫切除术转变为一期手术，避免了长时间颅内记录的需要。更广泛地说，该技术可能允许更有效地在个体患者中部署抗癫痫药物治疗，并通过直接证明治疗对间歇活动的影响，为测试新药物提供了一种手段。这项工作很可能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. PUBLIC HEALTH RELEVANCE: A technique, such as eMRI, that allows for more direct imaging of epileptiform discharges than is currently possible, is likely to be a powerful diagnostic tool for presurgical seizure focus localization, potentially transforming epilepsy resection into a one-stage surgical procedure, avoiding the need for prolonged intracranial recordings. More broadly, such an imaging tool would potentially allow for more efficacious deployment of antiepileptic medications in the individual patient, as well as providing a means for testing novel agents, by directly demonstrating their effects on cortical electrical discharges. This work is likely to deepen our understanding of the pathophysiology of epilepsy discharges and their spread.