T1 Hypointense Brain Lesions in NMOSD and Its Relevance with Disability: A Single Institution Cross-sectional Study

1. Background: T1 hypointense lesions are considered a surrogate marker of tissue destruction. Although there is a dearth of evidence about T1 hypointense brain lesions, black holes, in patients with Neuromyelitis Optica Spectrum Disorder (NMOSD), the clinical significance of these lesions is not well determined. 2. Objectives: The impact of T1 hypointense brain lesions on the clinical status and the disability level of patients with NMOSD, was sought in this study. 3. Methods: A total of 83 patients with the final diagnosis of NMOSD were recruited. Aquaporin-4 measures were collected. The expanded disability status scale (EDSS) and MRI studies were also extracted. T1 hypointense and T2/FLAIR hyperintense lesions were investigated. The correlation of MRI findings, AQP-4, and EDSS was assessed. 4. Results: T1 hypointense brain lesions were detected in 22 patients. Mean ± SD EDSS was 3.7± 1.5 and was significantly higher in patients with brain T1 hypointense lesions compared to those without them (p-value = 0.01). Noticeably, patients with more than four T1 hypointense lesions had EDSS scores ≥ 4. The presence of T2/FLAIR hyperintense brain lesions correlated with EDSS, as well (3.6±1.6 vs 2.3±1.7; p-value = 0.01). EDSS was similar between those with and without positive AQP-4 (2.7± 1.6 vs. 3.2± 1.7; p-value= 0.17). Also, positive AQP-4 was not more prevalent in patients with T1 hypointense brain lesions compared to those without them (50.9 vs 45.4%; p-value= 0.8). 5. Conclusion: We demonstrated that the presence of the brain T1-hypointense lesions corresponds to a higher disability level in NMOSD.