Free-water corrected diffusion tensor imaging (DTI) was able to detect white matter differences between patients with neuromyelitis optica spectrum disorder (NMOSD) and multiple sclerosis (MS), as published in Scientific Reports.

The authors found that the DTI measurements of the periependymal area surrounding the diencephalon and brain stem/cerebellum were significantly different between patients with aquaporin-4 (AQP4)-IgG-seropositive NMOSD and patients with MS. These results may indicate white matter injuries in areas with AQP4 in patients with NMOSD.

The specific measurements of fractional anisotropy (FA) and axial diffusivity (AD) were decreased (F =27.616, P <.001, F =7.336, P =.011, respectively) while radial diffusivity (RD) was increased (F =5.800, P =.022) in post hoc analysis of the voxels lining the third ventricle in patients with NMOSD.

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In multivariate analysis of covariance analysis, a significant difference was observed in the periependymal regions of the diencephalon the brain stem/cerebellar areas including the area postrema between patients with NMOSD and patients with MS (λ =0.462, P =.001).

Read more about NMOSD differential diagnosis

This analysis combined the diffusion tensor measures of FA, AD, RD, and mean diffusivity as dependent variables and age and expanded disability status scale (EDSS) scores as covariates. No significant difference between the 2 groups was observed in the lateral periventricular regions, however (λ =.790, P =.054).

“The use of free-water corrected DTI allows periependymal lining voxels in the third and fourth ventricles to be used to differentiate MS from NMOSD,” the authors said. “Future investigations will require a larger sample size, which can also lead to the development of a deep learning-based model for the differential diagnosis of MS and NMOSD.”

In total, the study included 44 patients (20 with NMOSD and 24 with MS) who underwent DTI between April 2014 and April 2020 at the Seoul National University Hospital in South Korea. All 20 of the patients with NMOSD were seropositive for AQP4 antibodies.

No significant difference was observed in sex, EDSS scores, percentage of treatment-naïve patients, percentage of patients who had brainstem lesions, and disease duration between the 2 groups. While not significant, the patients with NMOSD tended to have higher EDSS scores than the patients with MS. There was a significant difference between the 2 groups in regard to age, however (P =.001), with the NMOSD group having a higher age.


Kim M, Choi KS, Hyun RC, et al. Free-water diffusion tensor imaging detects occult periependymal abnormality in the AQP4-IgG-seropositive neuromyelitis optica spectrum disorder. Sci Rep. 2022;12(1):512. doi:10.1038/s41598-021-04490-3