Multimodal Magnetic Resonance Imaging Study Of Subjective Cognitive Decline And Mild Cognitive Impairment

Objective: To analyze the brain structure and function network abnormalities in patients with subjective cognitive decline(SCD),and to explore the evolution of default mode network(DMN)impairment in healthy volunteers(HC),SCD and mild cognitive impairment(MCI).Materials and Methods: According to the inclusion criteria,35 patients with SCD,88 patients with MCI and 32 normal controls were included.The subjects' related clinical data and neuropsychological scale were collected to assess the data,and the multimodal MRI data of the subjects were collected.The difference of brain structure between SCD and HC patients was analyzed by voxel based morphology(VBM).The brain regions with abnormal structure were used as seeds.The Functional connectivity analysis(FC)was used to analyze the difference of brain functional connectivity between SCD,MCI and HC.The PCC,anterior_mPFC and ventral_mPFC were used as seeds to analyze the differences between SCD,MCI and HC.Results:(1)VBM analysis results: compared with the healthy control,the volume of bilateral hippocampal tail in SCD patients are decreased and bilateral central lobule volume are increased.(2)The FC analysis results of hippocampus as seeds: compared with the healthy control,the functional connectivity was decreased in bilateral TPJ and bilateral mPFC,other side of hippocampu and parahippocampal in patients with SCD;the functional connectivity was decreased mainly in bilateral TPJ/ angular gyrus,bilateral mPFC,bilateral ACC,bilateral paracentral lobule,and no functional connection increased was found in patients with MCI.(3)DMN analysis results:(1)Taking PCC as seed point,compared with the healthy control,the functional connectivity was decreased in bilateral ACC,and increased in right frontal inferior gyrus in patients with SCD;the functional connectivity was decreased mainly in bilateral hippocampus and hippocampal gyrus,right superior frontal gyrus/left ACC,angular gyrus /right middle temporal gyrus,and increased inright precentral gyrus,bilateral insular/inferior frontal gyrus,right middle cingulate gyrus,right supplementary sports area,right Cerebellum in patients with MCI.(2)Using anterior_mPFC and ventral_mPFC as seed sites,compared with the control group,the functional connectivity between the right PCC and AMPFC decreased in SCD group,and no brain regions with functional connectivity between bilateral mPFC were found.The functional connection of the cingulate gyrus in the bilateral HIP/PHIP and bilateral PCC/ parts of the MCI group was reduced,and the functional connection between the right medial temporal gyrus and bilateral v mPFC was enhanced.Conclusions:(1)SCD patients have abnormal brain structure and brain function.This abnormality can be used as a biomarker for SCD.(2)MCI has a more extensive functional connection exception on the basis of the DMN function connection exception of SCD,indicating that SCD is the early state of MCI.