2.2. Patients and imaging

We included patients 18 years of age or older if they had been diagnosed with NMOSD as defined by the 2015 Wigerchuck diagnostic criteria [3] and presented an acute (≤30 days) exacerbation defined as new or worsening symptoms attributable to a new T2 or contrast-enhancing T1 lesion through magnetic resonance imaging (MRI). Each relapse what confirmed by MRI which was done in a Siemens Symphony 1.5 T. The standard protocol included Brain MRI: Axial T1 MT, SF orbits T1 SE FS, Axial, coronal T1 gadolinium, Axial and coronal T2 FS, DWI and ADC, axial and sagittal FLAIR, 3D sagittal FLAIR, Time of flight, gradient echo. Cervical and Thoracic MRI: Axial and sagittal T1 gadolinium, axial and sagittal T2, STIR.