Whole Brain VBM,DKI And Rs-fMRI Spontaneous Brain Activity Study In T2DM Patients With Early Cognitive Impairment

Purpose:To investigate the alterations of whole brain gray matter volumes,diffusion structures and spontaneous brain activities in type 2 diabetes mellitus(T2DM)patients with early cognitive impairment by using multi-mode magnetic resonance imaging(MRI),and its correlations with cognitive behavior and clinical measurements were analyzed,exploring the neuroimaging markers for diagnosis and treatment of early cognitive impairment in T2 DM patients.Method:(1)18 cases of early stage of T2 DM patients without any complications and 19 cases of well matched the gender,age,education healthy controls(HC)were enrolled.The whole-brain gray matter volumes were analyzed by using 3d-T1 BRAVO imaging,using voxel-based morphometry method on T1 structure imaging of two groups,and correlation analysis of two groups' whole-brain gray matter volumes differences with MMSE scores of two groups and HbA1 c level of T2 DM patients was researched.(2)Single-shot spin echo echo-planar imaging(SE-EPI)sequence was applied to collect two groups' data,DKI kurtosis and diffusion parameter values(MK,AK,RK,FA,MD,AD,RD)differences of the two groups' whole-brain voxels were automatically analyzed by using the voxel-based analysis(VBA)method,as well as the correlations with clinical variables and cognitive function scores were evaluated.(3)Tract-based spatial statistics(TBSS)were applied to investigate the different white matter of DKI parameters(MK,AK,RK,FA,MD,AD,RD)in T2 DM and HC groups,and white matter fiber tracts involved were evaluated.(4)Rs-fMRI was performed for two groups by the gradient plane echo sequence,and the ReHo values and ALFF values of the two groups were computed using the DPARSFA2.3 software based on Matlab 2013 a platform.The study determined the correlations of these differences with the MMSE scores of the two groups and the HbA1 c values of the T2 DM group.Results:(1)Compared with the HC group,The MMSE scores of T2 DM group were significantly reduced(P<0.001),and there were no significant differences in age,gender,education,BMI and blood pressure between the two groups(P>0.05).VBM results showed that the volumes of left triangle part of inferior frontal gyrus,orbital part of inferior frontal gyrus and opercular part of inferior frontal gyrus and left insula in T2 DM group decreased compared with HC group(P<0.001),and no brain areas with increased gray matter volumes were found in T2 DM group compared with HC group.Correlation analysis results showed that there was a significant positive correlation between left inferior frontal gyrus gray matter volumes and MMSE scores in the T2 DM group(r=0.55,p=0.02),and a significant positive correlation between left insula gray matter volumes and MMSE scores(r=0.51,p=0.03).(2)DKI results of VBA showed that compared with HC group,MK values of T2 DM group in the left limbic lobe,lingual gyrus,precuneus,splenium of corpus callosum,parahippocampal gyrus and the hippocampus,the left fusiform gyrus,left inferior occipital gyrus,middle occipital gyrus,inferior temporal gyrus,right fusiform gyrus,left cerebellum posterior lobe,left cerebellum crus area significantly increased(P<0.01),these results were attributed to an increase in AK and/or RK values.The results of kurtosis parameters values were more than those of diffusion parameters values.The results of correlation analysis showed that the AD values of the right lentiform nucleus in the T2 DM group were significantly positively correlated with the MMSE scores(r=0.53,p=0.02),the MD values of the right limbic lobe and the parahippocampal gyrus were negatively correlated with the MMSE scores(r=-0.41,p=0.09),and the RK values of the right precuneus were significantly negatively correlated with the HbA1 c values(r=-0.47,p=0.04).(3)DKI results of TBSS showed that white matter abnormal alterations of kurtosis parameters and the dispersion parameters in T2 DM group involved the left uncinate fasciculus,arcuate fasciculus,bilateral corona radiata,superior longitudinal fasciculus,inferior longitudinal fasciculus,superior fronto-occipital fasciculus,inferior fronto-occipital fasciculus,cingulum,thalamic radiation,corticospinal tract,anterior commissure,fornix,splenium of corpus callosum,the white matter of the cerebellum,hippocampus and parahippocampal gyrus areas.(4)Compared with HC group,the ReHo values of right triangle part of inferior frontal gyrus and right angular gyrus decreased in the T2 DM group(P<0.001),and increased in the right postcentral gyrus(P<0.001).Compared with HC group,the ALFF values of right posterior lobe of cerebellum,fusiform gyrus and right insula increased in T2 DM group(P<0.001).The results of correlation analysis showed that the ALFF values of the right insula in the T2 DM group were positively correlated with the MMSE scores(r=0.41,p=0.09).Conclusion:(1)In this study,VBM method was used to analyze the micro-structural alterations of the whole-brain gray matter volumes,and the results suggested that the decrease of the volumes of gray matter in the left inferior frontal gyrus and the left insula could result in cognitive impairment in T2 DM patients.(2)In DKI study,the diffusion structural abnormalities of whole-brain gray matter and white matter were automatically analyzed by using VBA and TBSS methods,the results of VBA suggested that the diffusion structural abnormalities of limbic system and other cognitive-related brain areas were the underlying mechanisms of early cognitive impairment in T2 DM patients,abnormal AD values in the right lentiform nucleus and MD values in the right limbic lobe and parahippocampa gyrus were associated with cognitive impairment,increased RK values in the right precuneus suggested that the patients were in the compensatory stage of cognitive impairment,the level of HbA1 c could influence whole brain micro-structure.TBSS results showed that the fornix,splenium of corpus callosum and posterior cingulum could be regarded as the white matter markers in the diagnosis of early cognitive impairment in T2 DM patients.(3)Combined with the ReHo and ALFF methods,the functional abnormalities of spontaneous brain activity in specific areas were detected,and ALFF values in the right insula were detected to be associated with the compensatory mechanism of cognitive impairment.These abnormalities would serve as neuroimaging markers for the early diagnosis of cognitive impairment in patients with T2 DM.