Olfactory FMRI In Early Diagnosis Of Alzheimer’s Disease

Objective:To discuss the clinical value and research value of olfactory fMRI in early AD diagnosis, and explore the exam method of olfactory fMRI in early AD diagnosis.Subjects and methods:14normal elders (NC),11MCI and AD patients underwent MMSE, MoCA and CDR grade. All subjects were scanned by Siemens3.0T MRI scanner with32channel head coil, in stimulate design with0.10%,0.33%,1.00%concentrations from low to high order, and the data was processed with Matlab7.11.0and SPM8software. We designated the primary olfactory cortex (POC) as the ROI, calculated the quantity of activated voxels and made group analysis, compared the quantity of activated voxels among the3groups. All the objects were analysed the correlation between the quantity of activated voxels and the MMSE, MoCA scores under the control factor of age. We compared the activated level of NC group and AD group with0.10%,0.33%,1.00%concentrations.Results:The quantity of activated voxels in POC of NC, MCI and AD group was201±114,88±102,45±60, the difference was statistically significant (H=13.272, P<0.01). The results of group analysis were:NC:470; MCI:151; AD:0. There was a positive correlation between the activated voxels and the MMSE (r=0.348, P<0.05), MoCA(r=0.362, P<0.05) scores under the control factor of age. The data of different concentration of three group:The quantity of activated voxels in POC of NC group with0.10%,0.33%,1.00%concentrations:48±20,105±37,78±48; MCI group:17±9.6,73±30,32±20; AD group:5.2±4.5,13±6.0,56±24.Conclusion:1, The activated level of NC, MCI and AD group reduced in sequence. Olfactory fMRI can reflect the olfactory functional defect due to AD pathologic change.2, Activated pattern of AD group was different from NC group’s with different stimulate concentration, so olfactory fMRI could observe activated level in POC area with different stimulate concentration, evaluate olfactory function level, and further evaluate the olfactory adaption and pathologic involvement in olfactory related brain area, reflect the early AD related pathological changes.