The Study Of Regional Homogeneity And Voxel Mirrored Homotopic Connectivity Of The Resting-state BOLD-fMRI In Alzheimer's Disease

Objective To investigate the changes of local spontaneous brain activity and functional connec-tivity between the voxels of equal position in terms of anatomical structure in both sides of the cereb-ral hemisphere of resting state in patients with Alzheimer' s disease(AD).Methods Including AD 24 patients diagnosed by the department of neurology and recruiting normal elderly control subjects 24 cases,who all undergo 3.0 T blood oxygenation level dependent resting-state Magnetic Resonance(BOLD-Rs-MR)scanning,the datas of all subjects have been given ReHo and VMHC analysis,through statistical analysis found that Re Ho abnormal functional regions,then using VMHC analyze functional connectivity condition between each pair of mirrored voxels in abnormal areas within the bilateral hemisphere.Results 1.Compared with healthy controls,the Re Ho value of AD group in bilateral superior medial frontal gyrus,middle-inferior orbitofrontal gyrus,the medial orbitofrontal,anterior-middle cingulate cortex,caudate nucleus,right hippocampus,right insular,right amygdala,right middle frontal gyrus and left superior-inferior temporal gyrus increased,decreased areas in bilateral middle occipital gyrus,superior occipital gyrus,calcarine,precuneus,posterior cingulate gyrus,precentral-postcentral gyrus,angular gyrus,inferior frontal operculum gyrus,left inferior parietal lobule,left middle frontal gyrus,left supplementary motor area and right superior frontal gyrus;at the same time,compared to healthy controls,the VMHC values of the bilateral olfactory gyrus,superior medial frontal gyrus,middle-inferior orbitofrontal gyrus,medial orbitofrontal gyrus,anterior cingulate gyrus and insular gyrus were higher,but the bilateral calcarine cortex,middle temporal gyrus and middle occipital gyrus were lower in AD group.2.Analyzing the distribution of abnormal brain regions of ReHo,compared with HC group,the brain regions with higher Re Ho value in AD patients located in the right middle frontal gyrus,right hippocampus,right amygdala,right island back and left inferior-superior temporal gyrus,there were no abnormalities of the VMHC analysis found in these areas.However,for the brain regions of bilateral cerebral hemisphere with incresed ReHo value which included medial frontal gyrus,orbital frontal gyrus,anterior cingulate gyrus and caudate nucleus,the reduced brain areas of bilateral cerebral hemisphere mainly located in the calcarine,mid-temporal gyrusand mid-occipital gyrus,the VMHC demonsrated abnormal functional connectivity between bilateral hemispheres in these regions.3.Analyzing ReHo statistics results showed that for same brain regions with abnormal Re Ho values in both sides of hemispheres in AD patients compared with healthy controls.The voxel-clusters and t-peak intensity in brain areas with Re Ho higher of right hemisphere relatively have increased compared to left hemisphere,but the voxel-clusters and t-peak intensity in brain areas with ReHo lower of left hemisphere relatively have increased compared to right hemisphere.Conclusion 1.Significant difference brain regions of ReHo and VMHC value between healthy control group and AD patients associated with brain functional areas of clinical memory and cognitive impairment.2.Compared to healthy controls,the alterations of function connectivity in bilateral hemisphere maybe connect with local spontaneous brain activity homogeneity in AD patients.3.AD compared with healthy controls,for the anatomical symmetry regions with changed Re Ho in the both sides of hemispheres,which the degree of activity in brain areas with Re Ho value having significant difference in both groups between left-right hemispheres were asymmetry,which may be related to the right dominant hemisphere.