初诊原发性甲减患者静息态脑功能的初步研究

A pilot study of resting-state brain function in naive patients with primary hypothyroidism

目的利用静息态分数低频振幅(fractional amplitude of low-frequency fluctuations,fALFF)技术探讨初诊原发性甲状腺功能减退症(甲减)患者脑损害的神经病理生理机制。材料与方法对25名初诊未治疗的甲减患者(甲减组)和19名健康对照(健康对照组)行认知心理量表评定和头颅MRI扫描,用两样本t检验比较全脑fALFF值的组间差异,并与临床变量及认知心理评分行Pearson相关分析。结果甲减组蒙特利尔认知评估量表评分减低(P=0.009),汉密顿抑郁量表-24和汉密顿焦虑量表评分增高(P=0.013;P=0.041),其左侧枕下回、舌回和右侧梭状回、枕上回、脑岛、中央后回的fALFF值减低(GRF校正,体素水平P<0.005,团块水平P<0.05),其中左侧枕下回、舌回和右侧梭状回的fALFF值与认知评分呈正相关(r=0.514,P=0.009;r=0.468,P=0.018;r=0.400,P=0.048)。当体素水平阈值降至P<0.001时,左侧舌回fALFF仍显著减低,且与认知评分呈正相关(r=0.547,P=0.005),另外,甲减组甲状腺素与抑郁评分呈负相关(r=-0.363,P=0.005)。结论甲减患者存在认知功能受损、抑郁及焦虑状态。静息状态下,多个与认知功能及情绪密切相关脑区的自发性神经元活动减低,可能是甲减患者认知功能受损及情绪异常的重要神经病理生理机制。

Objective:To explore the neurophysiological mechanisms of the brain damage in naive patients with primary hypothyroidism by using the fractional amplitude of low-frequency fluctuations(fALFF)of the resting-state functional magnetic resonance imaging(rs-fMRI).Meterials and Methods:Twenty-five untreated patient with hypothyroidism(hypothyroidism group)and 19 healthy volunteers(healthy control group)were assessed with cognitive psychological scales and cranial rs-fMRI scan.The two-sample t test was used to compare the difference of whole brain fALFF value between groups and Pearson correlation analysis with clinical variables and cognitive psychological scores.Results:In the hypothyroidism group,the cognitive scores of Montreal Cognitive Assessment(P=0.009),and the scores of Hamilton Depression Scale-24 and Hamilton Anxiety Scale increased(P=0.013;P=0.041).Compared to controls,the fALFF values in the hypothyroidism group were decreased in the left inferior occipital gyrus,lingual gyrus and right fusiform gyrus,superior occipital gyrus,insula,and central posterior gyrus(GRF correction,voxel level P<0.005,mass level P<0.05).Meanwhile,the fALFF values of left inferior occipital gyrus,lingual gyrus and right fusiform gyrus were positively correlated with cognitive scores(r=0.514,P=0.009;r=0.468,P=0.018;r=0.400,P=0.048).When the voxel decreased to P<0.001,the fALFF of the left lingual gyrus still decreased significantly and was positively correlated with Montreal Cognitive Assessment scores(r=0.547,P=0.005).Additionally,thyroxine was negatively correlated with depression scores in hypothyroidism group(r=-0.363,P=0.005).Conclusions:Patients with hypothyroidism have cognitive impairment,depression and anxiety.In the resting state,the spontaneous neuronal activity is decreased in multiple brain regions closely related to cognitive function and emotion,which may be a crucially neurophysiological mechanism of cognitive impairment and emotional abnormality in patients with hypothyroidism.