Changes In Cerebral Perfusion And Gray Matter Volume In Mild Alzheimer's Disease And Mild Cognitive Impairment

Objective: Using 3D pseudo-continuous arterial spin labeling(3D-pcASL)technology to study patients with mild Alzheimer's disease(AD)and mild cognitive impairment(MCI)patients with cerebral blood flow(CBF)perfusion and changes in cerebral gray matter volume characteristics.The correlation between CBF value of perfusion change area and Mini-mental State Examination(MMSE)scale in patients with mild AD and MCI was analyzed.Methods: From January 2018 to March 2019,patients with mild AD,patients with MCI and healthy controls were recruited from the department of neurology of shengjing hospital affiliated to China medical university in the dementia clinic of the department of neurology.GE Discovery 750 3.0T magnetic resonance scanner was used for MRI scanning with 3D-T1 WI and 3D-pcASL sequences.Useing SPSS 24.0 statistical software,Chi-square test and independent sample t-test were used to analyze the age,gender,education level and MMSE score of the three groups of subjects.The scanned 3D-pcASL sequence was pre-processed on a GE.750 workstation to synthesize a CBF map,convert it to NifTI format,check the image quality,and apply statistical parameter map software to the CBF map that meets the requirements.Perform preprocessing,including registration,segmentation,and spatial standardization(MNI standard brain),check the image quality again,apply DPABI plug-in to normalize and smooth all data,and finally use the statistical analysis function of SPM8 software for three groups of subjects The whole brain CBF map was statistically processed.The 3D-T1 WI image was converted to the NIfTI image format and the image quality was checked.The VBM8 plug-in under the SPM8 software was used for preprocessing to normalize the image into a same space(MNI standard brain).The image was divided and smoothed to obtain gray matter.,White matter,cerebrospinal fluid and other component images,using the gray matter image obtained in the previous step for statistical processing.Correlation analysis was performed between the CBF value and MMSE score of the brain regions with different perfusion.Results: A total of 26 patients with mild AD(age 73.0 ± 6.8 years,16 males),73 patients with MCI(age 74.6 ± 7.3 years,32 males),and 53 age and sex-matched healthy controls(age 73.7 ± 8.2 years,23 males)were included.Compared with the normal control group,the area of reduced CBF perfusion in the mild AD group is mainly located in the bilateral parietal lobe(mainly precuneus and angular),the occipital lobe,and the left temporal and frontal lobe,and the area of increased CBF perfusion is mainly located in the right hippocampus,parahippocampal,right cingulum and basal ganglia nucleus,and bilateral frontal lobe(mainly orbital and medial).The CBF reduction area in the MCI group is mainly located in the left medial superior frontal gyrus,medial and lateral cingulate gyrus,precuneus and central paralobular lobes,and the area of increased perfusion is mainly located in the right inferior temporal gyrus,fusiform,right hippocampus,and right precuneus and right lingual(P <0.01,FDR corrected,mass threshold> 100 volume).Compared with the MCI group,the areas with reduced CBF values in the mild AD group were mainly located in the left middle frontal gyrus,left left upper frontal gyrus,left upper temporal gyrus,left middle temporal gyrus,right angular gyrus of inferior margin,bilateral angular,bilateral ceneus,bilateral precuneus,the areas with increased CBF values in the mild AD group were mainly located in the right precentral,right thalamus,right hippocampus,right medial para-cingulate gyrus,right orbital frontal gyrus,right anterior cingulate gyrus,lateral cingulate gyrus,bilateral putamen(P <0.01,FDR corrected,mass threshold> 100 volume).Brain gray matter atrophy in patients with mild AD is mainly located in bilateral medial temporal lobe structures(hippocampus,parahippocampal gyrus,amygdala),and also involves bilateral insula and basal ganglia nucleus(P <0.01,FDR correction,mass threshold > 30 volume);gray matter atrophy areas in the MCI group are mainly located in the right inferior temporal gyrus,left middle temporal,peritalar cortex,medial and lateral cingulate cerebral gyrus(P <0.01,FDR correction,mass threshold> 30 volume).In the mild AD group,the CBF values of the left temporal parietal cerebral gyrus and bilateral superior frontal gyrus were positively correlated with the MMSE scores,the CBF values of the bilateral medial and lateral cingulate gyruses and the right anterior cingulate gyrus were negatively correlated with the MMSE scores;In the MCI group,the CBF values of the left upper frontal gyrus,the left precuneus,and the parietal lobule were positively correlated with the MMSE score,the CBF values of right inferior temporal gyrus,fusiform gyrus,right hippocampus,right precuneus,and right lingual were negatively correlated with MMSE scores(P <0.05).Conclusions: Patients with mild AD have hypoperfusion dominated by the left parietal lobe and hyperperfusion changes dominated by the right hippocampus,basal ganglia,and frontal lobe.MCI patients have hypoperfusion dominated by the left frontal lobe and right hippocampus.The main hyperperfusion changes,gray matter atrophy in AD patients are mainly concentrated in the bilateral temporal lobe structure.