儿童及青少年癫痫结构与功能MRI研究

Epilepsy is a common neurological syndrome, its therapy varies with different type and etiology. Nearly one-third of patients with focal epilepsy experience disabling seizures that are refractory to pharmacotherapy. Drug-resistant focal epilepsy is, however, potentially curable by surgery. In many patients, conventional MRI based on visual evaluation is unable to detect the surgical target(so-called idiopathic epilepsy).In recent years, the progress of MRI new technique has provided more helpful information for the lateralization and localization of epilepsy, but relative studies have mostly focus on adults.Clinically,the onset of epilepsy is generally in childhood,developing brain may impact neurocognitive function of epilepsy,MRI techniques have been rarely applied in children with epilepsy.Therefore,to detect the structural,functional changes and correlation with cognitive function of these patients and differentiate the pathological basis of the patients with refractory and non-refractory epilepsy is the current important scientific issues for understanding and clarify the pathophysiological mechanisms of epilepsy in children. According to a large number of recent documents and our studies, structural magnetic resonance imaging (sMRI) and functional MRI (fMRI) are sensitive to early reveal microstructural and functional changes of conventional MRI-negative epilepsy. In the present project, we aim to investigate brain structural,functional changes and correlation with cognitive function from whole brain level,to evaluate the locating diagnosis value of sMRI and rs-fMRI in children with epilepsy, to explore similarities and differences of the patients with epilepsy in children and adults,improving the understanding of epileptic pathophysiological mechanisms,providing a more scientific basis for drug treatment, prognosis and preoperative location of epilepsy.

癫痫是临床常见的神经系统疾病之一，其治疗方案因病因不同而不同，约1/3局灶性癫痫患者对药物治疗无效（难治性癫痫），而手术治疗效果较好。但部分难治性癫痫患者常规MRI不能发现病灶（特发性癫痫）。近年来，MRI新技术的进展为癫痫的定侧定位诊断提供了更多有用的信息，但主要集中在成人研究。临床上成人癫痫的发病多见于儿童期，又由于儿童脑发育的特点，其常伴有认知功能障碍，相关文献研究很少。基于此，探讨儿童癫痫的脑结构、功能变化及其与认知功能的相关性，分析难治性与非难治性癫痫的异同，是当前理解和阐明儿童癫痫病理生理机制的一个重要科学问题。根据大量的研究和申请人自己的工作积累，结构MRI和功能MRI能显示常规MRI阴性癫痫的微观结构及功能变化。本项目拟用结构与静息态fMRI从全脑水平探讨儿童癫痫脑结构、功能改变及其与认知功能的关系，评价其在儿童癫痫定侧定位诊断的价值，为癫痫疗效评估、预后判断提供新的视窗。

癫痫是由大脑皮层内神经元异常、过度、同步放电引起的大脑功能障碍及行为异常的临床综合征，通过多方面影响患者的认知、心理及社会活动等功能，儿童癫痫对认知功能损伤主要以言语表达和执行能力受损为主。采用多种MRI技术，从脑微观结构、功能及血流动力学水平探测癫痫患儿的异常，及其与认知损害之间的关系，为癫痫定侧、定位及结构、功能变化提供影像学证据。（1）应用基于脑表面形态学的分析，探讨16例特发性全面性癫痫（IGE）脑皮层的结构改变，并分析形态学异常脑区与病程的相关性。结果发现：与对照组相比，IGE组右颞中回皮层变薄，左颞中回表面积减小；左额下回中部、左外侧枕叶、右岛叶表面积增大；左颞上回体积减小。右颞中回皮层厚度与病程呈负相关性。（2）应用磁共振扩散峰度成像（DKI）研究34例儿童及青少年原发性癫痫的大脑改变，评价DKI在儿童及青少年癫痫患者病理生理机制研究的价值及与智商（IQ）的关系。结果发现：与对照组相比，脑电图双侧异常组中，FA值降低区域主要在双侧胼胝体、双侧岛叶、右侧额中回及颞上回、右侧扣带回、左侧中央前回及颞中回、左侧丘脑。MD值升高区域在左侧额叶及颞中回、右侧顶叶及扣带回、左侧中央前回、中央后回、左侧顶下小叶及左侧小脑半球。MK值降低区域在双侧额叶、颞叶、左侧顶叶。（3）利用静息态功能磁共振技术分析19例儿童及青少年特发性全面性癫痫（IGE）默认网络功能连接变化，探讨其与病程及智商（IQ）之间相关性。结果发现：与对照组比较，病例组DMN功能连接降低的脑区为双侧额中回、双侧背外侧额、额上回、双侧颞中回及右侧颞下回；功能连接增强的脑区为左侧眶部额上回及双侧楔前叶；左背外侧额上回功能连接强度与病程呈正相关。研究表明，采用多种MRI成像技术及分析方法，能发现儿童癫痫患者脑微观结构的形态学、血流动力学及功能连接异常，为癫痫的定侧定位诊断、预后评估、癫痫的病理生理机制研究提供新的生物学指标。