rs-fMRI对高原失眠者低氧暴露后脑结构与功能的对比研究

Comparative study of rs-fMRI on brain structure and function after hypoxia exposure in plateau insomniacs

目的:探讨体素形态学(Voxel-based morphometry,VBM)及静息态功能磁共振成像(Rest-state functional MRI,rsfMRI)方法对高原失眠者低氧暴露后脑结构与功能对比研究的价值。方法:招募50名援藏人员为研究对象,采用标准T1加权3D解剖图像及基于血氧水平依赖的rs-fMRI,于平原地区(海拔约200米)采集基线数据,入驻高原后9~12月,电话随访参与者,对自觉有失眠症状的进行召回,采用纸质问卷形式对参与者进行量表评估,对符合入组标准的13人再次于高原地区(海拔约3 200米)行MRI检查。对13例受试者入驻高原前后的脑形态及脑功能数据进行分析,并将脑功能有改变脑区与低氧暴露后患者的血氧饱和度及量表评分进行相关性分析。结果:入驻高原前后灰质体积(GMV)改变存在统计学意义(P<0.01),灰质萎缩的主要脑区位于双侧眶部额下回和右侧中央后回;低频振幅(ALFF)值改变存在统计学意义(P<0.01),ALFF值增加的主要脑区位于右侧角回;度中心性(DC)值变化存在统计学意义(P<0.01),DC值增加主要脑区位于右侧中央前回和右侧楔前叶。而局部一致性(ReHo)值、功能连接(FC)值数据均不存在统计学意义(P>0.01)。脑功能有改变脑区与低氧暴露后患者的血氧饱和度及量表评分之间无明显相关性(P>0.05)。结论:低氧暴露后失眠者大脑的结构与功能都存在变化,而且这种变化基本上是独立的,并具有非特异性。

Objective:To explore the value of voxel-based morphometry(VBM)and rest-state functional MRI(rs-fMRI)in the comparative study of brain structure and function after hypoxia exposure in plateau insomniacs.Method:Fifty Tibetan aid workers were recruited as research objects.Standard T1-weighted 3D anatomical imaging and rs-fMRI based on blood oxygen level were used.Baseline data was acquired in plain areas(approximately 200 m above sea level).After 9~12 months on the plateau,participants were followed up by telephone,those with insomnia symptoms were recalled,and 13 participants,who completed the questionnaire evaluation and met the enrollment criteria,underwent MRI examination again at the plateau area(about 3200 m above sea level).The brain morphology and function data of 13 subjects before and after settling on the plateau were analyzed,and then correlated with the brain areas with altered brain function and the blood oxygen saturation and scale score of the patients after hypoxia exposure was analyzed.Results:Compared with data before entering Tibet,there were significant changes in gray matter volume(GMV)after settling on the plateau(P<0.01),and the main brain regions of gray matter atrophy were located in the bilateral orbital inferior frontal gyrus and right posterior central gyrusand.Statistically significant changes in amplitude of low frequency fluctuation(ALFF)values exist(P<0.01).The main brain regions with increased ALFF values were located in the right angular gyrus.Statistically significant changes in degree centrality(DC)values exist(P<0.01).The main brain regions of increased DC value were located in the right anterior central gyrus and the right anterior cuneiform lobe.Plateau insomniacs showed no significant regional homogeneity(ReHo)or functional connectivity(FC)change(P>0.01).There was no significant correlation between the altered brain function and the blood oxygen saturation and scale score of patients after hypoxia exposure(P>0.05).Conclusion:There are structural and functional changes in the brains of insomniacs after hypoxia exposure,and these changes are largely independent and non-specific.