Structural network alterations in inferomedial temporal regions distinguishing relapsing-remitting multiple sclerosis from neuromyelitis optica spectrum disorder

초록

Introduction: Multiple sclerosis (MS) and neuromyelitis optica spectrum disorders (NMOSD) are inflammatory demyelinating diseases of central nervous system. Despite distinct immunopathology and difference in disease course and severity, there is a considerable overlap in clinical and imaging findings. Objectives: We investigated the alterations of white matter (WM) connectivity using graph theory in patients with MS and NMOSD. Methods: We analyzed structural connections using diffusion tensor imaging and graph theory in patients with relapse-remitting MS (N=68) and NMOSD (N=50), and 26 healthy controls (HC). Network-based statistic was employed to assess differences in WM connectivity among MS, NMOSD and HC groups. In addition, topological characteristics (global and nodal measures) were compared between three groups and its associations with clinical parameters, such as Expanded Disability Status Scale (EDSS) score and disease duration, were evaluated. Results: WM network analysis showed lower total strength, global and local efficiency in both MS and NMOSD groups, compared with HC group, without between-group differences. However, local efficiencies of the left hippocampus, parahippocampal gyrus, superior temporal gyrus, and the right Heschl’s gyrus were significantly decreased in MS compared with NMOSD. In addition, we identified two distinct subnetworks that characterized the disease groups. In MS, the most discriminative connectivity changes, compared with NMOSD, were located within the thalamus, hippocampus, parahippocampus, amygdala, fusiform gyrus, and inferior and superior temporal gyri. Network alterations were correlated with EDSS score and disease duration in both MS and NMOSD. Conclusions: Decreased global integration and local segregation of brain networks were identified in patients with MS or NMOSD. More extensive network dysfunction was present in MS and altered short connections within the thalamus and temporal, especially inferomedial temporal, regions were relatively spared in NMOSD compared with MS.