摘要目的 采用静息功能磁共振成像低频振幅(ALFF)技术,探讨颞叶癫痫脑活动的神经机制.方法 采用功能磁共振成像技术,观察伴有双侧海马硬化(HS)的内侧颞叶癫痫(mTLE)患者脑血氧水平依赖信号活动的改变.对南京军区南京总医院20例伴有HS的mTLE患者及20名正常志愿者进行静息态数据采集,并计算出各受试者ALFF值;采用两样本t检验,以P＜0.01水平观察TLE患者相对正常人,ALFF增高及降低的区域.结果 相比正常人,TLE患者BOLD信号ALFF改变的区域呈双侧对称分布.ALFF升高区域以边缘叶为中心进行分布:包括双侧海马旁回、杏仁核、脑干网状结构区、下丘脑、部分扣带回等边缘系统;双侧感觉运动区、枕叶、颞下回及眶额回等新皮层区;以及中脑腹侧及小脑内侧等皮层下结构,以右中央前回(15,-12,51)为最大ALFF增高区(T=6.02).ALFF幅度降低的区域包括:扣带回前部、内侧前额叶及楔前叶等经典缺省模式区域,双背外侧前额叶及颞上回,双豆状核头部、中脑背侧结构及小脑后叶等结构,以小脑(3,-78,-21)为最大ALFF降低区(T=-4.42).结论 ALFF功能磁共振成像技术可以对癫痫引起的脑活动改变情况进行观察.ALFF增高的脑区反映了大脑对癫痫活动的产生、传播等易化作用,边缘叶在TLE中起着重要作用;ALFF降低区域反映了大脑对癫痫活动的抑制,尤其是缺省模式功能的受抑制.

abstractsObjective To study the changes of amplitude of low-frequency fluctuation (ALFF) of the resting-fMRI in the mesial temporal lobe epilepsy (mTLE) with bilateral hippocampal sclerosis ( HS) , and discussed its underlying neuro-pathophysiological mechanism. Methods The resting-fMRI data of 20 TLE patients with HS and 20 normal volunteers were performed ALFF analysis. The amplitude of the blood oxygenation level-dependent activation of the resting-state brain was investigated. The brain structures showing increased and decreased ALFF in TLE patients were demonstrated by comparing to normal subjects with 2-sample t-test with threshold of P <0. 01. Results By comparison with that of normal subjects, the regions showing increased and decreased ALFF in TLE patients were distributed in the brain symmetrically and bilaterally. The regions showing increased ALFF were distributed with center of limbic system, such as parahippocampal gyri, araygdale, hypothalamus, dorsal anterior cingulate gyrus and part of posterior insular lobe, as well as the neocortices such as primary sensorimotor cortices, occipital cortices, inferior temporal gyri, orbital gyri, and the subcortical structures of verbal brainstem and mesial cerebellum. The point with maximal increased ALFF(T = 6. 02) located in the right precentral gyru (15, -12,51). While the regions showing decreased ALFF covered the areas of default mode, such as posterior cingulate cortex/ precuneus and medial prefrontal cortex /ventral anterior cingulate cortex, as well as other structures such as dorsal lateral prefrontal corties, superior temporal gyri, caudate heads, dorsal brain stem and the posterior cerebellum (3, -78, -21) with the maximal decreased ALFF(T= -4.42). Conclusion The method of ALFF allows the direct observation to the epileptic activation in TIE. The increased ALFF is considered the facilitation such as the epileptic activity generation and propagation; while the ALFF decrease is considered the function inhibition in these regions, especially implies the suspension in the default mode activity.