The Application Of Resting-state Functional Magnetic Resonance Imaging In Mild Cognitive Impairment And Alzheimer’s Disease

Objective:To investigate the difference of the functional connectivity within default-mode network related to posterior cingulated cortex between normal person, amnestic mild cognitive impairment (aMCI) patients and Alzheimer’s disease (AD) patients.And explore the potential value of resting-state functional magnetic resonance imaging in characterizing normal person, MCI and AD. The resting-state functional magnetic resonance imaging may provide some evidences for the early diagnosis of AD and MCI.Methods:10AD patients,10aMCI patients and10normal person were collected from hospital. There are6men and4women in the AD patients,the age range is65to80years and average is71.9; the are4men and6women in the aMCI patients,the age range is63to78years and average is69.3. There are7men and3women in normal person,the age range is60to75years and average is71.3. Conventional brain MR examination was performed in all people to exclude the possibility of cerebral infarction, hemorrhage, tumor, operation or trauma All subjects were performed resting-state fMRI scanning. The default-mode network based on seed region of posterior cingulated cortex was extracted from low frequency signal in fMRI data by using a temporal correlation method.Results:(1) The normal control group, aMCI group and AD group in the age, sex, level of education is no statistical difference, and the difference between the three groups of MMSE scale has a statistical significance.(2) In normal control group, areas showing functional connectivity to PCC included medial prefrontal cortex (MPFC), bilateral hippocampus, temporal pole, middle and inferior temporal gyrus, hypothalamus dorsal, cuneus, precuneus, superior parietal lobule (SPL), bilateral cerebellar hemisphere, vermis of cerebellum. Network structure has a good symmetry, functional connectivity is complete.(3) aMCI group and the normal control group have similar brain areas showing functional connectivity to PCC, but the range of brains decrease.(4) In AD group, areas showing functional connectivity to PCC included medial prefrontal cortex (MPFC), middle and inferior temporal gyrus, cuneus, precuneus, superior parietal lobule (SPL). Compared with the normal control group, the default brain areas in the network number and scope significantly reduces, the connectivity of bilateral hippocampus disconnect.Conclusion:The resting state function imaging as a brand new MRI (magnetic resonance imaging) method, make MRI technology no longer limited to the human brain morphology research, has expanded to the brain imaging fields. The default network for our proposed diagnosis provides new idea for the diagnosis of AD. The AD is a kind of disconnection syndrome. In MCI and AD patients functional connectivity based PCC with the default networks disrupt diagnostically and disconnect, and provides evidences for the early diagnosis of AD and MCI.