The Preliminary Study Of Neuromyelitis Optic Spectrum Disease Based On Diffusion Tensor Imaging

Objective:Two methods based on diffusion tensor imaging(DTI)technology,voxel-based analysis(VBA)and tract based spatial statistics(TBSS),were used to obtain the brain regions with different DTI parameter values(FA and MD values)in patients with neuromyelitis optica spectrum disease(NMOSD),and the correlation between the parameter values of the different brain regions and the extended Disability Status Scale(EDSS)was analyzed.To provide new imaging evidence for the changes of brain microstructure and neuropathological mechanism in NMOSD patients.Methods:A total of 20 NMOSD patients(case group)from October 2020 to November 2021 in the department of Neurology,Affiliated Hospital of Zunyi Medical University were enrolled,and 20 healthy volunteers(healthy control group)with matching age,gender,years of education and handedness were recruited in the same period.The case group met the NMOSD diagnostic criteria revised by the International Panel for Neuromyelitis Optica Diagnosis(IPND)in 2015.High-resolution 3D-T1WI,DTI,and T2-FLAIR were performed on GE Signal HDxt 3.0T MRI for all subjects to obtain corresponding images.FSL software was used for data preprocessing,voxel-based analysis(VBA)and tract-based spatial statistics(TBSS).DTI parameter values(FA value and MD value)of the whole brain gray and white matter of NMOSD patients and normal volunteers in conventional MRI were obtained,and the brain regions with differences were extracted,and their coordinates,voxel values and peak points were recorded.Finally,FA and MD values of different brain regions in case group and Spearman correlation with EDSS were analyzed.P<0.05 was considered as statistically significant difference.Results:(1)There were no significant differences in gender,age,education level and handedness between the case group and the control group(P>0.05).(2)The VBA post-processing technique,the brain regions with reduced FA values compared with the normal group have:bilateral cerebellum,bilateral posterior limb of the internal capsule,bilateral thalamus,bilateral hemiovale center,right temporal lobe,left superior parietal lobule,right truncus corporis callosi,anterior cingulate,the periaqueduct,left cerebral peduncle,right optic radiation,optic chiasma;FA value increased in the following brain regions:lingual gyrus(uncorrected,P<0.001).Correlation analysis showed that the left superior parietal lobule,left posterior limb of the internal capsule,left thalamus FA were negatively correlated with EDSS score.Brain regions with elevated MD values compared with the normal group were bilateral temporal lobe,bilateral insula,bilateral thalamus,bilateral putamen,medial frontal gyrus,the periaqueduct,left lingual gyrus(uncorrected,P<0.001).Correlation analysis showed that MD values of medial frontal gyrus and left thalamus were positively correlated with EDSS score.(3)The TBSS post-processing technique,the brain regions with reduced FA values compared with the normal group have:bilateral corona radiata,genu of the corpus callosum,body of corpus callosum,splenium of the corpus callosum,bilateral anterior limb of the internal capsule,bilateral posterior limb of the internal capsule,bilateral external capsule,bilateral cerebral peduncle,bilateral sagittal stratum,bilateral posterior thalamic radiation(optic radiation),bilateral middle cerebellar peduncle,bilateral medial lemniscus,bilateral fornix,bilateral corticospinal tract(TFCE,P<0.05).Correlation analysis showed that the FA values of the right cerebral peduncle,right sagittal stratum and bilateral posterior thalamic radiation(optic radiation)were positively correlated with EDSS score.Conclusion:Both post-processing technical analysis based on DTI showed that FA and MD values were changed in a wide range of brain regions of NMOSD patients with conventional MRI negative brain,and some brain regions were correlated with EDSS,providing a new imaging basis for abnormal changes of brain microstructure and neuropathological mechanism in NMOSD patients.