静息态功能MRI观察高海拔地区低氧暴露脑适应性变化及继发性失眠者脑结构及功能改变

Resting-state functional MRI observation on adaptive changes ofbrain after hypoxic exposure at high altitude areas and brainstructural and functional changes in secondary insomnia

目的 以静息态功能MRI(rs-fMRI)观察正常成年人高海拔地区低氧暴露后大脑适应性变化及继发失眠者脑结构和功能改变。方法 纳入26名援藏工作人员,于入藏前及入藏6个月后采集颅脑结构高分辨率三维T1WI和rs-fMRI,并根据临床评估结果将其分为失眠组(n=8)及非失眠组(n=18);对比受试者入藏前、后及组间入藏后脑结构及功能改变。结果 相比入藏前,入藏后左侧额中回、左侧海马旁回及右侧顶下缘角回灰质体积缩小(P均<0.01),右侧小脑局部一致性增加(P<0.01),左侧舌回、左侧颞中回及左距状裂周围皮质分数低频振幅(fALFF)增加(P均<0.01)。相比非失眠组,入藏后失眠组左侧后扣带回fALFF增加(P<0.01)、左侧眶部额上回度中心性减低(P<0.01)。结论 正常成年人高海拔地区低氧暴露及出现继发性失眠者多个脑区结构及功能发生改变。

Objective To observe normal adults brain adaptive changes after hypoxic exposure in high altitude areas,as well as brain structural and functional changes in secondary insomnia using resting-state functional MRI(rs-fMRI).Methods Totally 26 Tibetan aid workers were enrolled,and high-resolution three-dimensional structural T1WI and rs-fMRI of brain were acquired before and 6 months after admission to Tibet.According to clinical evaluation results,the subjects were divided into insomnia group(n=8)or non-insomnia group(n=18).Brain structural and functional changes of all 26 subjects were compared before and after entering Tibet,also between insomnia and non insomnia groups after entering Tibet.Results Compared with those before entering Tibet,gray matter volume decreased in the left middle frontal gyrus,left parahippocampal gyrus and right inferior parietal angular gyrus(all P<0.01),while regional homogeneity increased in the right cerebellum(P<0.01),and the fractional amplitude of low-frequency fluctuation(fALFF)increased in the left lingual gyrus,left middle temporal gyrus and cortex around the left calcarine fissure after entering Tibet(all P<0.01).Compared with those of non-insomnia group,after entering Tibet,fALFF increased in the left posterior cingulate gyrus and degree centrality decreased in the left orbital superior frontal gyrus in insomnia group(both P<0.01).Conclusion After hypoxic exposure in high altitude areas,structural and functional changes existed in multiple brain regions in normal adults and secondary insomnia.