基于同步EEG-fMRI的MRI阴性颞叶癫痫致痫网络的特征和干预研究

Temporal lobe epilepsy is the most common type of refractory epilepsy，of which surgical approach is considered as the most effective treatment. Epilepsy pre-surgical evaluation is challenging, especially for those with a negative magnetic resonance imaging (MRI) finding, who often need invasive intracranial electrodes recording before the curative surgery. In addition, postoperative outcome of these patients with negative MRI is usually poor. Epileptogenic network is considered to play a vital role in seizure initiation and matainence. Therefore, further understanding of the characteristics of epileptogenic network of temporal lobe epilepsy with negative MRI may help change the current situation. Based on our prior simultaneous electroencephalography-functional MRI (EEG-fMRI) studies on focal epilepsy patients, in this project, we aim to delineate the epileptogenic network related to interictal epileptic discharges and explore the dynamic changes within the network in MRI negative temporal lobe epilepsy patients based on EEG-fMRI; to validate the epileptogenic network property using post-surgical outcome as gold standard; to discuss the impact of post-surgical outcome by targeting different part of the network. The differences of network property between those patients with favorable outcome and those with poor outcome will also be explored, in order to discover neuroimaging biomarker for post-surgical outcome. The predicted results may pave the way for non-invasive pre-surgical evaluation in MRI-negative temporal lobe epilepsy patients and provide neuroimaging biomarker for post-surgical outcome.

颞叶癫痫是最常见的耐药性癫痫类型，约占所有耐药性癫痫的2/3，外科治疗被认为是其最有效的治疗方式。癫痫术前评估是世界公认的难题，MRI阴性颞叶癫痫的评估更具挑战性，多需要侵入性的颅内植入电极记录进行评估，且手术预后不尽人意。致痫网络在癫痫发生发展中起重要作用，阐明MRI阴性颞叶癫痫的致痫网络特征将有利于改变现状。本项目拟在课题组前期基于同步脑电图-功能磁共振成像（EEG-fMRI）对局灶性癫痫的研究基础上，以MRI阴性颞叶癫痫为研究对象，采用同步EEG-fMRI成像技术，探索个体化的发作间期癫痫样放电相关的致痫网络及网络内部动态变化特征，以手术预后为金标准验证所发现的致痫网络特征，探讨手术对致痫网络不同部位的干预作用，对不同预后患者的致痫网络特征进行比较研究，力图探寻预测手术预后的影像学指标。研究结果将可能为MRI阴性颞叶癫痫的无创性术前评估提供新的思路，并为手术预后的预测提供影像学指标。

颞叶癫痫是最常见的耐药性癫痫类型，约占所有耐药性癫痫的2/3。致痫网络在癫痫发生发展中起重要作用，阐明颞叶癫痫致痫网络特征将有助于理解其发病机制，同时将有利于提高疗效。我们利用同步EEG-fMRI技术研究了MRI阴性颞叶癫痫发作间期癫痫样放电相关的致痫网络，结果发现在癫痫样放电发放时，颞叶内侧结构、颞叶新皮质、及远隔脑区出现BOLD信号激活,同时在默认网络相关脑区出现负激活。我们通过动态功能连接的分析方法还发现，瞬时的颞区癫痫样放电发放时，海马与默认网络相关脑区功能连接降低，而杏仁核与“奖赏系统”相关脑区功能连接增强，提示短暂的癫痫样放电对意识水平、情绪等功能产生影响。另外，我们通过非匹配负波检查还发现颞叶癫痫患者不仅在乳突区（颞区）还在额中央区非匹配负波潜伏期延长，再次说明颞叶癫痫是一种网络疾病。我们还研究了颞叶癫痫患者在术前、术后3月、6月、12月、24月白质纤维的动态变化情况，即脑结构网络变化，研究发现了三种不同模式的白质纤维FA改变，模式一：术后3月白质纤维FA值降低，之后稳定；模式二：术后白质纤维FA值逐渐升高；模式三：FA值在术后3月短暂下降，随后逐渐上升，这反应了癫痫手术后白质纤维存在截然不同的“恢复”模式。本项目的研究结果有助于进一步理解颞叶癫痫的网络机制。