Brain MRI features at chronic phase in NMOSD patients

Introduction: Chronic brain lesions are under reported compared to acute lesions in the spectrum of neuromyelitis optica (NMOSD). Its associations range from astrocytopathy itself, comorbidities and no specific lesions. Objectives: To describe the frequency, characteristics and distribution of chronic lesions in patients with NMOSD in remission, with clinical associations. Methods: In this cross-sectional study, we evaluated anti-aquaporin-4 positive NMOSD patients who were in remission for at least 12 weeks. All patients underwent brain MRI at the same 3.0 T scanner and the images were reviewed by two experienced neuroradiologists. Results: A total of 60 patients (54/6 women/men; mean age +- SD of 42.2 +- 11.2 years) were included. MRI abnormalities were detected in 45 (75%) patients. Encephalic typical NMOSD features occurred in 30 (50%) patients, classified in 5 categories (periventricular hyperintensity (31.7%) postrema area lesion (31.7%); large hemispheric lesions (10%); corticospinal tracts lesions (6.7%); diencephalon (1.7%)). Nonspecific lesions were identified in 30 patients and other types of lesions in 18 patients. Only 2 patients showed typical MS lesions. We found significant associations between brain MRI abnormalities and longer disease duration (p=0.002) delayed diagnosis (p=0.004) and number of relapses (p=0.044). No associations were found between MRI typical NMOSD lesions and age, EDSS and vascular/autoimmune comorbidities. Conclusions: Brain MRI abnormalities are frequent in NMOSD patients and are associated with disease duration, delayed diagnosis and previous number of relapses.