| Objective :To investigate the change of default mode network characteristics in patients with vascular mild cognitive impairment(Va MCI)by posterior cingulate functional connectivity(FC)and different band at fractional amplitude of low-frequency fluctuation(f ALFF),and to analyze the relationship between DMN and cognitive function.Methods :All the subjects were from the Second Hospital of SHANXI Medical University neurology department outpatient,inpatient and physical examination between July 2016 and February 2017.22 cases of Va MCI patients as the research object,and compared with21 sex-,age-and education level-matched healthy subjects with normal cognitive function as control group.The above two groups based on blood oxygen level dependent(BOLD)Rs-f MRI scanning,compared two groups of subjects of interest area in the posterior cingulate(PCC)differences between FC and other brain regions and in the classical band(0.01-0.08Hz),slow-5 bands and slow-4 bands(0.01-0.027Hz)under the f ALFF,cleared changes of Va MCI in patients with DMN.Then a correlation analysis was performed between the change of DMN and the Montreal Cognitive Assessment(Mo CA)scores in patients with Va MCI.Results :1.Va MCI group's MMSE score(25.55 ± 1.92),Mo CA score(18.59 ± 3.63)and Mo CA subitems in the visual space or executive function(2.59 ±1.09),attention or computing power(2.77± 0.92),language(1.5± 1.06),abstract ability(0.23 ± 0.43),and delayed recall(3.23 ± 1.15)subitem scores were significantly lower that in the normal control group(28.29 ±0.96,27.71±1.06,4.05±0.59,5.86 ± 0.36,2.81 ± 0.41,1.81± 0.41,4.24 ± 0.94,all P<0.05),while the Mo CA subitems in the naming(2.63 ± 0.58)and orientation(5.18 ±1.22)subitems in Va MCI were not significantly different with that in the control group(2.71±0.56?5.86±0.36,both P>0.05).2.The analysis of the two groups showed that there was a wide range of FC and f ALFF values in the brain areas of the Va MCI group and the control group,including the posterior cingulate cortex,precuneus and the inferior parietal lobe.Among the two groups,the f ALFF and FC values of the posterior cingulate gyrus and the precuneus were the highest in group.3.There were extensive DMN changes in the intracranial compared with the controls:(1)Va MCI patients' FC decreased with posterior cingulate cortex of the brain nnected with whole brain function in the control group: the Anterior cingulate cortex,right orbital frontal gyrus,left inferior temporal gyrus and left orbital frontal gyrus,all were located in the default brain network area,not found significantly enhanced brain FC.(2)classic band(0.01-0.08Hz)f ALFF: right precuneus and right superior temporal gyrus f ALFF decreased;on the left orbital frontal gyrus and left inferior temporal gyrus increased f ALFF.(3)sub-band f ALFF in slow-5 band(0.01-0.027Hz)of the right inferior temporal gyrus,cerebellum and left angular gyrus f ALFF decreased;while in the right lingual gyrus,left superior temporal gyrus showed the increased of f ALFF value.In the slow-4 band(0.027-0.073Hz)superior parietal lobe,left inferior temporal gyrus and left dorsolateral frontal gyrus f ALFF decreased;in the right superior temporal gyrus and right insula increased f ALFF.4.Va MCI group was related to Mo CA score: the f ALFF value of left angular gyrus was positively correlated with Mo CA score in the slow-5 band.Conclusion :1.Va MCI patients showed abnormal posterior cingulate functional connectivity patterns in the resting state.2.There were abnormal spontaneous activities in the default mode network of Va MCI patients,and the abnormal active brain regions of Va MCI patients have different spatial distribution characteristics of abnormal spontaneous activity in different frequency bands;3.The spontaneous changes in abnormalities in the left side angular gyrus of the slow-5 frequency group are positively correlated with the Mo CA score,and this finding could provide a functional imaging basis for the clinical diagnosis of Va MCI... |
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