| Objective:With the acceleration of the aging of the global population,various neurodegenerative diseases related to aging have seriously affected the quality of life in the elderly,attracting more and more attention from the whole society,among which Alzheimer's Disease(AD)is an important issue affecting the life in the elderly.AD is a progressive degenerative disease,whose pathological changes may progress decades before the onset of clinical symptoms.At present,no effective drug treatment has been found for dementia AD,and the current phase III clinical trials for dementia AD have failed.Therefore,more and more researchers propose to move forward the diagnosis and treatment of AD.Mild cognitive impairment(MCI)is an intermediate stage between normal aging and dementia.It is a high risk factor of dementia.Among them,amnestic mild cognitive impairment(aMCI)is mainly manifested as memory impairment,and its conversion rate to AD is significantly higher than that of other types of MCI.This suggests that intervention with aMCI may be effective in slowing or even stopping the progression of dementia.Resting state functional magnetic resonance imaging(Rs-fMRI)is a kind of common brain imaging technology,by detecting the human body spontaneous brain hemodynamics resting state oscillation information indirectly reflect the inherent neural activity patterns of the brain,it has the advantages of noninvasive,simple operation,matching degree is high,identify the functional pathology effectively,etc.Rs-fMRI including local brain activity,brain interval functionconnection and the network analysis of three parts,including these amplitude of low frequency fluctuation(ALFF)is mainly used in brain research of local activities.ALFF has been widely used in cognitive disorders,but at present,the number of subjects included in the single brain imaging studies carried out by various research centers is generally small,and the results are not stable enough.The results of individual brain imaging are likely to be influenced by specific experimental procedures,such as scan parameters.The interpretation of the function of a brain region in a single brain imaging study is often limited to the use of a single or several tasks.In this study,activation likelihood estimation(ALE)is used to maximize the location consistency between the studies.Minimize the subjectivity of the analytical method.At present,more and more researchers have found that the use of Rs-fMRI can improve the diagnostic rate of aMCI and provide scientific basis for the early diagnosis and intervention of AD.This study conducted a Meta-analysis of the clinical study on the ALFF in patients with aMCI and healthy controls,to systematically evaluate the application of Rs-fMRI in patients with aMCI,aiming to explore the imaging markers for early diagnosis and treatment of AD.Methods:Computer retrieval database both at domestic and abroad,and according to the limit of retrieval word retrieval from built libraries to December 2018 in both English and Chinese published about aMCI patients associated with Rs-fMRI high quality case-control study,according to the standards set by the retrieval of literature filtering,by two independent researchers for quality evaluation and information extraction,extraction of related data,then use the brain regions activated likelihood evaluation method(ALE)meta analysis was carried out on the extraction of brain imaging data.Results:A total of 16 articles were included,with a sample size of 966 cases,including483 cases in aMCI group and 483 cases in healthy control group,15 groups ofpatients with aMCI were involved in the experiment activation weakening coordinates compared with the healthy control group,67 activation weakening coordinate points were extracted from 904 subjects.Compared with the healthy control group,14 groups of patients with aMCI were involved in the study of activation enhancement coordinates,and 43 activation enhancement coordinate points were extracted from 818 subjects.According to the score of the Newcastle-Ottawa Scale(NOS)for literature quality evaluation(6 ~ 8),indicating that the literature quality was good.The results of Meta-analysis showed that there were bilateral posterior cingulate gyrus,left precuneus lobe,left inferior frontal gyrus in the area with lower ALFF in aMCI group than in healthy control group.The areas with higher ALFF values were bilateral parahippocampal gyrus.Conclusions:1.Compared with the healthy control group,aMCI patients had abnormal ALFF of resting state functional magnetic resonance.2.The aMCI patients had abnormal ALFF values in the bilateral posterior cingulate gyrus,left precuneus lobe,left inferior frontal gyrus,bilateral parahippocampal gyrus: the areas with lower ALFF values were bilateral posterior cingulate gyrus,left precuneus lobe,left inferior frontal gyrus,the areas with higher ALFF values were bilateral parahippocampal gyrus.3.The abnormal results of Rs-fMRI ALFF can be used as imaging markers for early diagnosis of aMCI. |
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