A Diffusion Tensor Imaging Study Of White Matter Differences Between Autoimmune And Viral Encephalitis

Objective(s): The purpose of this study was to explore the comparison of brain white matter microstructure changes in patients with autoimmune encephalitis(AE)and viral encephalitis(VE)by diffusion tensor imaging(DTI),and the diagnostic ability of DTI for encephalitis of diverse etiologies.Methods: Prospectively collecting patients diagnosed as AE and VE in the First People’s Hospital of Yunnan Province and healthy controls(HC)for fluid-attenuated inversion recovery(FLAIR)sequence and DTI scanning.The differences between AE and VE patients in FLAIR were compared.Based on Tract-based Spatial Statistics,the differences in DTI parameters between all encephalitis patients and the HC group were compared.Then,the differences in DTI parameters among AE,VE and HC groups were respectively compared by using t-test for two-group comparison and analysis of variance for three-group comparison.A p-value of <0.05 was considered statistically significant.The DTI parameters correlation with the clinical characteristics of patients was analyzed.Meanwhile,the diagnostic and differential diagnostic efficacy of DTI parameters for AE and VE was evaluated by receiver operating characteristic curve(ROC).Results: There was no statistical difference in FLAIR imaging between patients with AE and VE(p> 0.05).Reduced MD,RD values of the bilateral anterior thalamic radiation,corticospinal tract in the encephalitis group compared to the HC group(p <0.05).The comparison among AE group,VE group and HC group showed that the FA and AD values in VE group were significantly lower than those in AE group.Compared with HC group,FA and AD values in AE group were significantly higher,while those in VE group were significantly lower.Compared with HC group,MD and RD values in AE group and VE group were significantly higher(p<0.05).There was a correlation between the MD value and RD value of the forceps major,Anterior thalamic radiation,corticospinal tract of the encephalitis group and imaging score,course of disease,modified Rankin Scale score(p<0.05).The AD value of the right inferior frontooccipital fasciculus in VE group was positively correlated with course of disease(r =0.542,p = 0.024).The FA value of the right corticospinal tract had the best diagnostic efficiency between AE and VE,with a sensitivity of 73.9% and a specificity of 94.1%(AUC=0.898,p < 0.001).Conclusion(s): Encephalitis patients showed extensive changes in brain white matter microstructure,and there was a correlation between the damage of certain white matter fiber tract microstructures and clinical features.Compared with AE patients,VE patients had more significant and persistent damage in cerebral white matter microstructure,and subacute early AE patients may have compensatory remodeling of cerebral white matter microstructure compared with the HC group.DTI has potential as a diagnostic tool for distinguishing white matter changes in AE and VE.