Development of Hardware and Software for Clinical MEG

描述(由申请人提供)：本提案的主要目标是使用循证方法论来评估脑磁图(MEG)作为评估和计划癫痫患者手术治疗的临床工具。在无法检测到发作间期棘波或发作活动的患者中，我们将在简短的脑磁图检查中评估定位癫痫皮质的方案，方法是：1)使用先进的分析方法(LCMV波束形成器和MR-FOCUSS)定位异常的高频振荡和慢波；以及2)停用短效巴比妥钠或3)停用迷走神经刺激。我们将验证这些先进的脑磁图分析技术和现有的单等效电偶极(ECD)方法对抗皮层脑电(ECoG)，并确定它们的敏感性和特异性。为了使复杂的部分性癫痫患者受益，我们将使用脑磁图来研究棘波的时间和传播，并使用扩散张量成像(DTI)纤维束成像来识别潜在的网络，以区分具有一致传播模式的多灶性癫痫和单灶性癫痫。我们将通过比较发作间期棘波的同时MEG和ECoG定位来确定MEG是否足以替代难治性癫痫的侵入性术中标测。在应用空间滤波器(LCMV波束形成器)后，将比较在ECoG电极位置处观察到的尖峰波形的相似性和分布与脑磁图信号。我们还将验证功能性MEG语言和记忆成像作为颈内动脉旁路手术(IAP，WADA测试)的非侵入性替代方法的敏感性和特异性，方法是证明MEG提供的空间和时间分辨率对于成像涉及语言和记忆的皮质源活动的序列和演变是必要的；具体而言，1)MEG语言和记忆偏侧性指数与WADA测试的值一致；2)MEG语言和记忆成像符合直接电皮质刺激标测(DECS)；以及3)MEG语言和记忆成像协议是可靠的(测试对象的可重复性)。我们将通过与已建立的ECD匹配(如果可行)和符号学对皮质电成像的比较来确定高级分析方法的敏感性和特异性。我们将通过检验一组易于检验的假设来实现这些目标。因此，拟议研究的完成将使脑磁图成为一种有用和可靠的诊断工具。公共卫生相关性：这项提案的总体目标是将脑磁图扩展为评估和规划癫痫患者治疗的临床工具。本研究的目的是将脑磁图建立为一种可靠的临床诊断工具。

DESCRIPTION (provided by applicant): The overarching goal of this proposal is to use evidence-based methodology to evaluate Magnetoencephalography (MEG) as a clinical tool for evaluation and planning of surgical treatment for patients with epilepsy. In patients where interictal spikes or ictal activity are not detectable, we will evaluate protocols for localizing epileptic cortex during brief MEG exams, by 1) localizing abnormal high frequency oscillations and slow waves using advanced analysis methods (LCMV beamformer and MR-FOCUSS); and 2) withdrawal of a short-acting barbiturate or 3) withdrawal of vagus nerve stimulation. We will validate these advanced MEG analysis techniques and the existing single equivalent current dipole (ECD) method against electrocorticography (ECoG), and determine their sensitivities and specificities. To benefit patients with complex patterns of partial epilepsy, we will use MEG to study the timing and propagation of spikes, and use diffusion tensor imaging (DTI) tractography to identify the underlying network to distinguish multifocal epilepsy from unifocal epilepsy with consistent patterns of propagation. We will determine if MEG, alone, is sufficient to replace invasive intraoperative mapping for intractable epilepsy by comparison of simultaneous MEG and ECoG localizations of interictal spikes. Similarity and distribution of spike waveforms observed at the locations of the ECoG electrodes will be compared to MEG signals after a spatial filter (LCMV beamformer) has been applied. We will also validate the sensitivity and specificity of functional MEG language and memory imaging as a noninvasive alternative to the intracarotid amobarbital procedure (IAP, Wada test) by demonstrating that the spatial and temporal resolution provided by MEG is necessary to image the sequence and evolution of cortical source activity involved in language and memory; specifically 1) that MEG language and memory laterality indices agree with those from the Wada test; 2) that MEG language and memory imaging agrees with direct electro-cortical stimulation mapping (DECS); and 3) that MEG language imaging protocols are reliable (testing intrasubject reproducibility). We will determine the sensitivity and specificity of advanced analytical methods by comparison with the established ECD fit (when feasible) and semiology to electrocorticography. We will accomplish these goals by means of examining a set of readily testable hypotheses. Thus the completion of the proposed studies will establish MEG as a useful and reliable diagnostic tool. PUBLIC HEALTH RELEVANCE: The overall goal of this proposal is to extend MEG as a clinical tool for evaluating and planning treatment for patients with epilepsy. The objective of this study is to establish MEG as a reliable clinical diagnostic tool.