Comparison of acute myelitis findings on MRI in MOGAD, AQP4 NMOSD, and multiple sclerosis

Sagittal MRI of an adult patient with MS shows a short T2 hyperintensity at C2 extending 1.5 vertebral segments in length (A, arrow). Axial image shows the lesion is located peripherally in the right lateral column (B, arrow). Sagittal (C) and axial (D) postcontrast T1-weighted MRI show associated ring enhancement of the spinal cord lesion (C, D, arrows). Sagittal (E) and axial (F) MRI of a patient with myelitis accompanying AQP4 NMOSD shows a longitudinally extensive T2 hyperintense lesion extending more than three vertebral segments (E, F, arrows). Associated ring enhancement of the cord lesion is seen on sagittal (G, lower arrow) and axial (H, arrow) postcontrast T1-weighted MRI, along with more homogeneous enhancement (G, upper arrow). In a patient with myelitis accompanying MOGAD, sagittal MRI shows a longitudinally extensive T2-hyperintense lesion extending more than three vertebral segments (I, arrows). On axial images, the lesion involves predominantly gray matter, forming an H sign (J, arrow). Postcontrast T1-weighted gadolinium images show no enhancement (K, L).