Multi-mode Study Of Dementia Of AD By Combiningresting-state FMRI And MRS In PCC

Objective1.To explore the feature of brain activity changes in resting-state in patients with Alzheimer’s disease by resting-state BOLD-fMRI amplitude of low-frequency fluctuation．2. To measure the metabolic changes in PCC in patients with Alzheimer’s disease by single-voxel protonmagnetic resonance spectroscopy.Materials and MethodsTwenty cases of AD and Twenty matched healthy controls，while the Resting-state BOLD-fMRI data and single-voxel1H-MRS date in PCC were recorded by a Siemens3.0T Trio MR scanner. The Resting-state BOLD-fMRI data preprocessing was performed using DPARSF(data processing assistant for resting state fMRI),the ALFF analysis was performed using REST software., and the REST Slice View software was used to view the anatomical locations of the ALFF differences between the two groups．Siemens3.0T TrioTim MR workstation was used to detect levels of N-acetyl aspartate(NAA), myo-inositol(mI), creatinine (Cr)and choline (Cho) in PCC. The ratios of NAA/Cr, Cho/Cr, mI/Cr, NAA/mI were compared by a independent sample t test.Results1. Compared with controls, AD patients showed significantly decreased ALFF value in PCC/PCu,bilateral frontal cortex, bilateral inferior parietal cortex, and significantly increased ALFF value mainly in the bilateral parahippocampal gyrus, bilateral fusiform, right frontal-parietal lobe, right cerebellum posterior lobe and basal ganglia. Our results suggested that the slow-5band might be more sensitive in detecting abnormalities of spontaneous brain activity in the basal ganglia, however, the slow-4band might be more sensitive in detecting abnormalities of spontaneous brain activity in the bilateral parahippocampal gyrus and fusiform.2. Compared with normal group, the ratio of NAA/mI and NAA/mI were significantly decreased and the ratio of mI/Cr was significantly increased in posterior cingulated gyrus in AD patients.Conclusion1.Most of the brain showed significant differences in the spontaneous neuronal activity in AD patients, spontaneous neuronal activity in some brain regions is frequency-dependent, neuronal compensatory mechanism existed in wide-spread brain regions;2.AD patients had significant differences metabolic levels in PCC, magnetic resonance spectrum technology can be used for early screening and preliminary diagnosis for the AD patients...