多模态磁共振结合种子点及纤维追踪法评价颞叶癫痫患者默认网络功能和结构的结果分析

Analysis of function and structural characteristics of default network in patients with temporal lobe epilepsy using multimodal magnetic resonance imaging combined with seed-based connectivity analysis and fiber tracking

目的运用多模态磁共振结合种子点和纤维追踪方法研究颞叶癫痫患者默认网络的功能及结构特点。方法对41例颞叶癫痫患者(颞叶癫痫组)和31例健康人(对照组)行磁共振扫描,运用基于种子点方法提取与种子点功能相关的脑区,选择功能连接显著差异脑区作感兴趣区。采用基于确定性纤维追踪方法获得两组差异脑区的各向异性分数(FA)、纤维数量、纤维长度并比较,对差异脑区功能连接强度与其FA、纤维数量、纤维长度相关性进行分析。结果颞叶癫痫组与种子点功能相关的脑区仅分布于左侧枕中回、左侧中央前回、左侧楔前叶、左侧背外侧额上回、左侧缘上回、右侧额中回、右侧颞上回、右侧小脑下脚。对照组与种子点功能相关的脑区分布于左侧眶部额下回、左侧楔前叶、左侧颞中回、左侧小脑下脚、右侧额中回、右侧三角部额下回、右侧海马旁回、右侧角回、右侧颞中回、右侧小脑下脚,两组默认网络显著差异的脑区为双侧内侧额上回,其功能连接强度明显下降(P<0.05)。颞叶癫痫组的双侧额上回白质FA、纤维数量明显小于对照组(P<0.05),而两组纤维长度比较,差异无统计学意义(P>0.05)。颞叶癫痫组默认网络差异脑区功能连接强度与FA、纤维数量、纤维长度无明显相关性(P>0.05)。结论颞叶癫痫患者存在默认网络功能连接异常,差异脑区纤维连接完整性、纤维数量受损。

Objective To investigate function and structural characteristics of default network in patients with temporal lobe epilepsy using multimodal magnetic resonance imaging combined with seed-based connectivity analysis and fiber tracking. Methods Magnetic resonance imaging scanning was performed in 41 patients with temporal lobe epilepsy （temporal lobe epilepsy group） and 31 healthy persons（ control group）. Brain regions related to seed points function were abstracted using seed-based connectivity analysis ,then the brain region with significant difference in functional connectivity were selected as the region of interest. Fractional anisotropy （FA）, fiber number, and length in the brain region with difference were obtained using the deterministic fiber tracking and then compared between the two groups. The correlations between the connection strength of brain region with difference and FA,fiber number, and length were analyzed. Results The brain regions related to seed points function in temporal lobe epilepsy group only distributed in the left occipital gyrus,left precentral gyrus, left precuneus,left dorsolateral frontal gyms, left supramarginal gyrus, right middle frontal gyrus, right superior temporal gyms, and right inferior cerebellar peduncle. The brain regions related to seed points function in the control group distributed in left inferior frontal orbital,left precuneus,left temporal gyrus, left cerebellar peduncle, right middle frontal gyrus, right triangle of inferior frontal gyrus, right parahippocampal gyrus, right angular gyms, right middle temporal gyrus, and right inferior cerebellar peduncle. Bilateral medial frontal gyrus was the region with significant difference of the default network, and its connection strength significantly decreased in the temporal lobe epilepsy group compared to the control group （ P 〈 0.05 ）. FA and the fiber number of the white matter in bilateral superior frontal gyrus in temporal lobe epilepsy group were significantly less than those in the control group（P 〈 0.05 ）, but there was no significant difference in the fiber length between the two group（P 〉0.05 ）. No correlation with difference between the connection strength of brain region and FA,fiber number and length were found in temporal lobe epilepsy group （P 〉 0.05）. Conclusion Patients with temporal lobe epilepsy have abnormal function of the default network and impaired fiber connectivity completeness and fiber number in brain regions with differences.