Structural MRI Study On Olfactory Center And FMRI Study On Olfactory Functions

Objective: To measure the normal value of the olfactory structure volume of the healthy Chinese adults by using MRI technique,and discuss their variation with age and evaluate whether volumes of olfactory structure variation in parallel to olfactory function. Make smoker’s response to the smoking olafctory cue under different physiological status by using the functional the magnetic resonance imaging, and seek how the smoking olafctory the cue impact the smoker’s physiological and a psychological factors. To explore the changes of brain function and structure in the T2 DM with olfactory dysfunction by using Resting-state functional magnetic resonance imaging and VBM to investigate the correlation of these changes.To evaluate olfactory clinical diagnostic value of olfactory and cognitive dysfunction of diabetes mellitus.Material and methods: 103 healthy right-handed volunteers were randomly selected to participate the in our study for measuring OB volumes and evaluating the correlation between OB volume and age. 107 healthy right-handed subjets were randomly the selected to participate in our study. Volumetric measurement was performed by manual segmentation of the consecutive 1-mm thick the coronal slices through the OBT in the left hemisphere and the right one separately. All subjects were lateralized olfactory tests(Sniffin’ Sticks) to the judge of olfactory functions involving odor threshold. Seventeen man smokers’ five man nonsmokers underwent this study.All of them used a cigarette as stimulus, paper for control.We adopted a block the design in this experiment. MRI examination was the performed on 1.5T MRI using echo the planner imaging sequence.13 diabetes mellitus patients with olfactory dysfunction, 19 diabetes mellitus patients without olfactory dysfunction and 20 cases of healthy controls wereincluded in this study. Regionalhomogeneity and amplitude of low frequency fluctuation were calculated with the software of REST.Using analysis of variance and two independent samples t test to compare the differences Re Ho values、ALFF value and gray matter volume in three groups.Results: 1.There was remarkable correlation between OB absolute volume and olfactory functions correspondingly. The males’ absolute OB volumes of either left-side or right-side were respectively larger than females’. Pearson’ partial correlation analysis with ICV as a covariate revealed that significant negative correlations were presented between age and the volume of right EC, both sides of PRC and both sides of short insular cortex. MANOVA revealed that there were significant age-group differences in the olfactory function including three kinds of olfactory function and their sum score. Significant negative correlations were found between age and the scores of Sniffin’ Sticks tests.Pearson’ partial correlation analyses controlling for ICV revealed a significant positive correlation between the volume of PCR and THR on the right side, and a significant positive correlation between the volume of PRC and DIS on the right side. Furthermore, a significant positive correlation was presented between the volume of long insular cortex and DIS on the left.2. When smokers were exposed to the smoking a olfactory cue in the abstinent state, we could find the activation on olfactory structure.When the smokers were exposed to the smoking olfactory cue in the satiated state. After the paired test of the smoker’s response to the smoking olafctory the cue under different physiological status(satiated vs. abstinent), we could find the the more notable activation on the prefrontal lobe、the left callosal gyrus、the right middle temporal gyrus、right thalamus in the smoking forbidden a state.There were no the statistical differences between the satiated and the abstinent status in both sides of the cerebellum.3. DM group compares NC group shows ALFF value reduction in bilateral precuneus and right lingual gyrus. DM group compares NC group shows Re Ho value reduction in bilateral lingual gyrus, hippocampus, cerebellar vermis, the left inferior temporal gyrus, bilateral cerebellar.Correlation analysis showed that negative correlation between the volume of precuneus and blood glucose、VFT and C-peptide in DM group.Conclusion:1. The present study provided the normal range of a relatively large sample size of olfactory structure among healthy Chinese adults. The physiological variation of OB volumes decreased with age, and there were evident age-related volumes reduction of olfactory structure in our study.2.The Limbic system and the prefrontal loab and the paly an important role in the cue-induced smoking craving,and this is a experiment the approved this theory from the new perspective the of the olfactory.3.Thecognitive, olfactory and visual brain regions in T2 DM patients appear function and morphology damage,the brain regions that a compensatorymechanism may exists. The effective monitoring of olfactory function may be a reliable indicator of the occurrence of cognitive impairment in T2 DM patients.