ABSTRACT
Objective To observe the characteristics of brain activation of multiple sclerosis (MS) patients and healthy controls at functional magnetic resonance imaging (fMRI) with olfactory stimulation,determine the locations of activation in areas of olfactory center and explore the MS olfactory related network.Methods Eighteen MS patients from the Affiliated Hospital of North Sichuan Medical College from February 2017 to March 2018 were enrolled as MS group,and 20 matched healthy adults during the same period served as controls.The Visual Analogue Scale was used to evaluate olfactory function in all subjects,the rest structure MRI was performed first,and volatile gases of lavender and rose solution were used to alternately stimulate olfactory during fMRI scanning.The brain activation was obtained by using matlab2013a and SPM8 softwares.The distribution and quantity of demyelination lesions were counted on T2 weighted image,and Spearman correlation analysis was done with SPSS 17.0 software package.Results The activated brain areas in the healthy control group included bilateral middle frontal gyrus,bilateral insula,bilateral supramarginal gyrus,bilateral orbitofrontal gyrus,right thalamus,right central anterior gyrus,bilateral cingulated gyrus,bilateral hippocampus,bilateral amygdala and bilateral superior frontal gyrus (t =2.11,P＜0.05).The activated brain areas in the MS group included right cerebellum,left insula,left superior temporal gyrus,right inferior frontal gyrus (t=2.19,P＜0.05).Compared with the control group,the MS group showed statistically significant decrease in activated values in right insula,right amygdala,right inferior frontal gyrus,right frontal middle gyrus,and the left supramarginal gyrus (t=2.04,P＜0.05).The distribution and number of demyelination lesions and major activation of brain regions with olfactory in the MS group demonstrated no significant correlation (r=-0.524,P=0.054).Conclusions Multiple brain areas involved in the olfactory processing and olfactory-related brain network existed.The activation of olfactory center had dominance in the right brain.The activation of the brain area in the MS group was significantly reduced,and the activation voxel and activation intensity were weakened.The olfactory-related brain network changed in MS patients.The distribution and number of demyelination lesions had no significant effect on the major activation of brain regions with olfactory stimulation.