磁共振NODDI技术对阿尔兹海默病和遗忘型轻度认知障碍海马体微观结构的研究

目的利用神经突方向离散度和密度成像(neurite direction dispersion and density imaging,NODDI)分析阿尔兹海默病(Alzheimer's disease,AD)和遗忘型轻度认知障碍(amnestic mild cognitive impairment,aMCI)患者双侧...

A study on the microstructure of hippocampus in Alzheimer's disease and amnestic mild cognitive impairment based on NODDI

Objective:Using neurite direction dispersion and density imaging(NODDI)to analyze the changes in the microstructure of the bilateral hippocampus in patients with Alzheimer’s disease(AD)and amnestic mild cognitive impairment(a MCI),to provide more information on the pathogenesis of AD and explore clinical value of NODDI technology for AD and a MCI.Materials and Methods:Fifteen patients with aMCI,20 patients with AD and 20 normal controls(NC)was recruited for prospective NODDI scanning,using MRIcro software to measure the three groups of bilateral hippocampal neurite density index(NDI),neurite direction dispersion index(ODI),and volume fraction of isotropic water molecule(Viso).The differences of each parameter among the three groups using single-factor analysis of variance was compared,LSD was used to test the differences between groups.For the different parameters,Spearman correlation analysis was used to analyze the correlation between the parameters and the MMSE score and the MoCA score to obtain the correlation coefficient r.Results:Compared with the NC group,the bilateral hippocampal NDI value and ODI value of the aMCI group and the AD group were significantly lower than the NC group,the difference was statistically significant(P<0.001);the Viso value was significantly higher than the NC group,and the difference was also statistically significant(P<0.001).The aMCI group and the AD group were compared between the groups.The Viso value of the AD group was significantly higher than that of the aMCI group,and the difference was statistically significant(P<0.001),while the difference between the NDI value and the ODI value was not statistically significant(P>0.05).Correlation analysis shows that the left hippocampal NDI value(r=0.656,P<0.001)have the strongest positive correlation with the MMSE score,and the left Viso value(r=-0.690,P<0.001)has the strongest negative correlation with MMSE score;at the same time,the left hippocampal NDI value(r=0.632,P<0.001)has the strongest positive correlation with MoCA score,and the left Viso value(r=-0.629,P<0.001)has the strongest negative correlation with MoCA.Conclusions:The number,volume and arrangement complexity of bilateral hippocampal neurites in the a MCI stage and AD stage are significantly reduced,which provides more reference data for exploring the pathogenesis of AD.At the same time,during the progression of a MCI to AD,the bilateral hippocampal Viso value may become an important evaluation index,which has important value for the identification,follow-up and prognosis evaluation of a MCI and AD.