QSM对无轻度认知功能障碍的2型糖尿病病人脑内铁沉积的评估

Cerebral iron deposition on quantitative susceptibility mapping in patients with type 2 diabetes mellitus but without mild cognitive impairment

目的 探讨不伴有轻度认知功能障碍(MCI)的2型糖尿病(T2DM)病人脑内铁含量改变,及其与认知功能改变的相关性。方法 前瞻性纳入不伴MCI的T2DM病人27例(T2DM组)及健康对照30例(HC组),2组性别、年龄相匹配,均进行认知功能和情绪状态评估并完成定量磁化率成像(QSM)。在QSM图上手动勾画兴趣区(ROI),包括双侧尾状核、壳核、苍白球、丘脑、红核、黑质、小脑齿状核,测定每个ROI内磁化率值。采用独立样本t检验、卡方检验比较2组的临床资料和ROI内磁化率值,采用配对t检验比较2组内同一脑区双侧ROI的磁化率值。以年龄、性别、教育年限作为协变量,在T2DM组中对2组间存在差异的量表评分和磁化率值进行偏相关分析。结果 与HC组相比,T2DM组蒙特利尔认知评估(MoCA)量表评分中的命名能力评分及右侧丘脑磁化率值较低,MoCA量表抽象能力评分较高(均P<0.05)。双侧脑区磁化率比较显示,T2DM组的左侧齿状核磁化率值高于右侧,HC组的右侧黑质磁化率值高于左侧(均P<0.05)。T2DM组的右侧丘脑磁化率值与MoCA量表内抽象能力评分呈负相关(r=-0.548,P=0.005)。结论 不伴MCI的T2DM病人以右侧丘脑铁含量降低为主,且与部分认知功能异常相关,丘脑铁沉积改变可能成为T2DM病人认知功能改变的影像学标志。

Objective To investigate the changes of the cerebral iron deposition and the relationship between the alternative iron content and the cognitive function in type 2 diabetes mellitus(T2DM) patients without mild cognitive impairment(MCI). Methods A total of 27 T2DM patients without MCI(T2DM group) and 30 healthy controls(HC group) were prospectively included. The two groups were matched for gender and age. Cognitive function and emotional state were evaluated, and quantitative susceptibility mapping(QSM) was completed. Regions of interests(ROIs) were manually drawn on the QSM map,including bilateral caudate nucleus, putamen, globus pallidus, thalamus, red nucleus, substantia nigra, and cerebellar dentate nucleus. Magnetic sensitivity values were measured from each ROI. The independent sample t-test and Chi-square test were used to compare the clinical data and the magnetic susceptibility values between the two groups, and the paired t-test was used to compare the susceptibility values between ipsilateral and contralateral brain regions in the two groups. Using age,gender, and years of education as covariates, partial correlation analysis was performed in the T2DM group for the scale scores and magnetic susceptibility values showing differences between the two groups. Results Compared with the HC, the score of naming ability of MoCA and susceptibility value in the right thalamus were significantly decreased, and the score of verbal abstraction of MoCA was increased in the T2DM group. In the T2DM group, the susceptibility value of the left dentate nucleus was higher than that of the right one. In the HC group, the susceptibility value of the right nigra was higher than that of the left one(P<0.05). The susceptibility value of the right thalamus was negatively correlated with the verbal abstraction function of MoCA in the T2DM group(r=-0.548, P=0.005). Conclusion The decrease of iron content mainly involves in right thalamus in T2DM patients without MCI, and the alteration is associated with cognitive performance change. The alteration of the iron deposition in thalamus may be an imaging marker for the alternative cognitive function in T2DM patients.