Multimodal MRI Study Of Hippocampus In Relapsing-remitting Multiple Sclerosis Patients

Purpose: The 3.0T MRI resting state functional imaging(fMRI)technique and diffusion tensor imaging(DTI)were used to investigate the hippocampal function and structure in patients with relapsing remitting multiple sclerosis(RRMS).To study the local brain function,function connection with whole brain and volume changes in the hippocampus of RRMS patients at resting state,will help clinicians further discover the intrinsic pathological mechanism and intervention measures.Method:Patient collection: 20 patients with RRMS who were visited in the Department of Neurology of the Chian and Japanese Union Hospital of Jilin university were collected,and there were 16 healthy subjects with matching age,sex,and education to be selected.Then all subjects were tested for montreal congnitive assessment(MoCA)and expanded disability status scale(EDSS)within one week before or after MRI examination.A 3.0T magnetic resonance scanner was used to test the 3DTIW1,BOLD-EPI,and DTI for both groups and process the data.Using REST software to extract the bilateral hippocampus as the region of interest,the strength of functional connectivity(FC)between the bilateral hippocampus and the whole brain,Regional Homogeneity(ReHo)and amplitude of low-frequency fluctuation(ALFF)were calculated and analyzed separately.And SPM software is used to calculate the bilateral hippocampal DTI parameters(FA value,MD value).The general conditions and clinical scores of the two groups were tested using SPSS 20.0 software for two-sample t-tests.The FC,ReHo,and ALFF results plots were analyzed using REST software with a statistical analysis program for two-sample t-tests between groups.The DTI parametric result plots were compared using the two-sample t-test using SPM8 software.The Pearson correlation analysis was performed between the EDSS and MoCA scale scores,FC abnormal areas,ReHo abnormal areas,AFLL abnormal areas,and DTI parameters of the RRMS group.Result:(1)The MoCA scores in patients with RRMS(t =-4.920,P = 0.002)are significantly lower than those in the HC group.(2)Compared with HC group,there are cingulate,marginal,and right brain stems in the left hippocampus and the brain with weakened functional connections in the MS group;there are the right cerebellum(post-cerebellar),double Lateral temporal lobe,inferior parietal lobe,frontal lobe(prefrontal lobe,middle frontal lobe),amygdala,pale globus lateral,lenticular nucleus in the brain enhanced areas.The right brainstem,marginal lobe,mid-temporal gyrus,parahippocampal gyrus,and left-frontal lobe are in the brain regions with weakened functional connections between the right hippocampus and the whole brain;the right region of the cerebellum(posterior cerebellum),the left occipital region,left frontal lobe,insula,parietal lobe are in the enhancement region(P?0.001,corrected by AlphaSim,voxel?5).(3)Compared with the HC group,the ReHo values in the left hippocampus,marginal lobe,and parahippocampal gyrus of RRMS patients are decreased,and part of the hippocampus,temporal lobe,marginal lobe,and parahippocampal gyrus are increased in the ReHo values;the right hippocampal gyrus,marginal lobe,hippocampus and temporal lobe have higher ReHo values,and the difference is statistically significant(P?0.05,corrected by AlphaSim,voxel?5).(4)Compared with the HC group,after the left hippocampus is used as a template,the ALFF values in the brain regions are decreased in the MS group: left hippocampus,limbic lobe,parahippocampal gyrus,temporal lobe,and caudate nucleus;Increased in the brain regions: marginal lobe,parahippocampal gyrus,hippocampus and amygdala.After the right hippocampus is used as a template,ALFF values in the brain regions are decreased: hippocampus,marginal lobe,temporal lobe,parahippocampal gyrus and amygdala;the following ALFF values show to increase height: hippocampus,parahippocampal gyrus and marginal lobe(P?0.05,corrected by AlphaSim,voxel?5).(5)Compared with HC group,there is a significant difference in the FA value between the bilateral hippocampus in the MS group(P?0.001,voxel?5).RRMS patients have higher MD values in the left hippocampus than in the HC group and the difference is statistically significant(P?0.001,voxel?5).(6)There is correlative between the left hippocampal whole brain functional connection strength and MoCA score(r=-0.698,P=0.025),right hippocampal whole brain functional connection strength and EDSS score(r=-0.649,P=0.042).The left hippocampal MD values are negatively correlated with MoCA scores(r=-0.729,P=0.017),and are positive correlated with EDSS scores(r=0.653,P=0.041);right hippocampal MD values and EDSS scores(r=0.684,P=0.029)are positive correlation.The right hippocampal ALFF values are positively correlated with the right FA values(r=0.693,P=0.026).The right hippocampal ReHo values are negatively correlated with the right FA values(r=-0.709,P=0.022).Conclusion:(1)In the RRMS patients,the whole brain and local functional connections in the hippocampus have both enhanced and weakened areas.The left hippocampus with abnormal cognitive function is associated with cognitive function.The right hippocampal abnormal functional connectivity is related to the degree of disability.(2)The structural abnormality of hippocampus in RRMS patients is related to cognitive function and degree of disability.The right hippocampal is more pronounced than the left side.(3)There is a correlation between the right hippocampal local functional connection and the abnormal hippocampal structure on the same side.