Abstract: Objective  To study the distinction of abnormal brain activity in mesial temporal lobe epilepsy (mTLE) with hippocampal sclerosis (HS) or other pathogical basis, and to discuss their underlying pathophysiological mechanism in mTLE.  Methods  Thirty mTLE patients with unilateral hippocampal sclerosis (mTLE-HS) and 30 mTLE patients with occupying lesion in unilateral temporal lobe (mTLE-OL) were investigated by comparing with 30 age- and sex-matched healthy subjects. MRI data were collected using a Siemens 3.0T scanner, and all of the participants were studied using amplitude of low-frequency fluctuation (ALFF) analysis of resting state fMRI. A cost-function modification was used for image preprocessing, then the difference of extratemporal mALFF changes between the two groups of mTLE patients were analyzed with two-sample t test, and the correlation between mALFF and epilepsy duration of mTLE were also investigated.  Results  In the resting state, mTLE-HS patients and mTLE-OL patients all showed significant changes in mALFF in extratemporal structures, but the distribution patterns of changes in brain were different. Compared with mTLE-HS, the mTLE-OL patients showed increased mALFF in bilateral inferior parietal lobes, precuneus, angular gyrus, middle and posterior cingulate gyrus and contralateral middle temporal gyrus, while mALFF reducing was observed in contralateral postcentral gyrus, bilateral middle occipital gyrus and cerebellum (P < 0.05, AlphaSim corrected), that is to say, the default mode network (DMN) in mTLE-HS were inhibited more seriously than in mTLE-OL patients. Correlation analysis showed that no significant correlation was found between mALFF and epilepsy duration in mTLE-HS patients; mALFF in bilateral middle and posterior cingulate gyrus was positively correlated with epilepsy duration in mTLE-OL patients (r = 0.687, P = 0.000), while mALFF in bilateral anterior cingulate gyrus was negatively correlated with epilepsy duration (r = -0.621, P = 0.000).  Conclusions  mTLE with different pathological basis showed different distribution patterns of abnormal brain function, which indicated that their latent pathophysiological mechanism might be different, further confirming mTLE-HS was a specific type of epilepsy.

Key words: Epilepsy, temporal lobe, Magnetic resonance imaging, Hippocampus

摘要： 目的 研究不同病理基础内侧颞叶癫痫患者异常脑功能活动分布模式的差异，探讨异常活动脑区在内侧颞叶癫痫发病过程中的病理生理学机制。方法 采用基于低频振幅（ALFF）的静息态fMRI 技术，分别对30 例单侧海马硬化性内侧颞叶癫痫（mTLE-HS）和30 例单侧占位性内侧颞叶癫痫（mTLE-OL）患者进行研究，并与30 例性别和年龄相匹配的正常对照者进行比较。经代价函数预处理图像后，REST 软件计算全脑低频振幅均值并作归一化处理获得mALFF 值，两样本t 检验依次对3 组被试mALFF 值进行比较，对比mTLE-HS 和mTLE-OL 颞叶外脑区mALFF 值变化，并分析mALFF 值改变脑区与癫痫病程之间关联性。结果静息态下，mTLE-HS 组和mTLE-OL 组患者均呈现颞叶外mALFF 值改变，但异常脑区分布模式不同。与mTLE-HS 组相比，mTLE-OL 组患者mALFF 值增强区域位于双侧顶下叶、楔前叶、角回、扣带中后回和对侧颞中回；mALFF 值减弱区域为对侧中央后回、双侧枕中回和小脑（均P < 0.05，AlphaSim 校正），提示mTLE-HS 较mTLE-OL 脑默认网络受抑制程度更为严重。mTLE-HS 患者局部mALFF 值与癫痫病程无明显关联性，而mTLE-OL 患者双侧扣带中后回mALFF 值与病程呈正相关（r = 0.687，P = 0.000），双侧前扣带回与病程呈负相关（r = -0.621，P = 0.000）。结论 不同病理基础内侧颞叶癫痫存在不同的异常脑功能活动分布模式，提示二者潜在的病理生理学机制可能不同，验证了mTLE-HS是一种特异性癫痫类型。

关键词: 癫痫, 颞叶, 磁共振成像, 海马