基于低频振幅和局部一致性的视神经脊髓炎谱系疾病认知功能障碍的静息态脑功能成像研究

Alterations in amplitude of low frequency fluctuation and regional homogeneity in patients with neuromyelitis optica spectrum disorder and cognitive impairment:A resting-state functional magnetic resonance imaging study

目的探究伴认知功能障碍的视神经脊髓炎谱系疾病(neuromyelitis optica spectrum disorder,NMOSD)患者静息态脑功能低频振幅(amplitude of low frequency fluctuation,ALFF)及局部一致性(regional homogeneity,ReHo)的改变。材料与方法前瞻性招募34名NMOSD患者及39名健康对照者进行静息态磁共振扫描及神经心理学评估,将患者根据认知评估划分为认知障碍组(n=16)及认知保留组(n=18),采用ALFF及ReHo分析探究认知障碍组、认知保留组患者及健康对照三组间自发性脑活动的差异。基于MATLAB的DPABI软件进行数据分析处理,采用两两对比的独立样本t检验对3组受试者的ALFF及ReHo脑图进行组间比较,提取差异脑区的ALFF及ReHo值与NMOSD患者的临床资料及认知分数进行相关性分析。结果认知障碍组左侧尾状核及海马旁回ALFF值显著高于认知保留组,左侧尾状核ALFF值显著高于健康对照组,左侧中扣带回ReHo值显著低于健康对照组(GRF校正,体素水平P<0.001,团块水平P<0.05)。差异脑区的平均ALFF值、平均ReHo值与NMOSD患者多项认知测试分数显著相关,左侧尾状核、海马旁回的ALFF值与患者的复发次数呈正相关(P<0.05)。结论左侧海马旁回、尾状核及中扣带回的自发活动异常可能参与了NMOSD患者认知功能下降的神经机制。

Objective:To investigate the alterations in amplitude of low frequency fluctuation(ALFF)and regional homogeneity(ReHo)in cognitively impaired patients with neuromyelitis optica spectrum disorder(NMOSD).Materials and Methods:Thirty-four patients with NMOSD and 39 healthy controls were included and underwent neuropsychological evaluations and resting-state functional magnetic resonance imaging scanning.Patients were classified as cognitively impaired(n=16)and cognitively preserved(n=18).ALFF and ReHo analyses were used to explore the differences in brain spontaneous activity among the cognitively impaired,cognitively preserved and healthy control groups.Data were processed and analysed using the DPABI toolbox based on MATLAB.Two-sample t-tests were used for comparisons of ALFF and ReHo between each two groups.ALFF and ReHo values in brain regions that showed statistical significance were extracted for correlation analysis with clinical and neuropsychological data in the whole NMOSD group.Results:The cognitively impaired group showed significantly higher ALFF in the left caudate nucleus and left parahippocampal gyrus compared to the cognitively preserved group,significantly higher ALFF in the left caudate nucleus compared to the healthy control group,and significantly lower ReHo in the left middle cingulate cortex compared to the healthy control group(P<0.001 at voxel level and P<0.05 at cluster level,GRF corrected).ALFF and ReHo values in brain regions with statistical significance showed significant correlations with multiple cognitive test scores in NMOSD patients.Also,ALFF values in the left caudate nucleus and parahippocampal gyrus were positively correlated with the number of relapses in patients(P<0.05).Conclusions:Abnormal baseline brain activity in the left parahippocampal gyrus,caudate nucleus and middle cingulate cortex may be implicated in the neural mechanisms of cognitive decline in patients with NMOSD.