Comparison of brain MRI in multiple sclerosis (MS), aquaporin-4–IgG seropositive neuromyelitis optica spectrum disorder (AQP4 NMOSD), and myelin oligodendrocyte glycoprotein-IgG antibody-associated disorder (MOGAD)

Axial postcontrast T1-weighted MRIs show optic nerve enhancement extending less than half the length of the nerve in a patient with MS (A, arrow), whereas AQP4 NMOSD has a predilection for the optic chiasm (B, arrows) and MOGAD is typically associated with bilateral anterior optic nerve pathway enhancement extending more than half the length of the optic nerve (C, arrows). Axial FLAIR images reveal peripheral small T2-hyperintense lesions in the dorsal pons typical of MS (D, arrow); an additional characteristic inferior temporal pole lesion of MS is also noted (D, arrowhead); a peri-fourth ventricle/area postrema T2-hyperintense lesion is seen in the patient with AQP4 NMOSD (E, arrow), whereas bilateral fluffy middle cerebellar peduncle T2-hyperintense lesions are typical of MOGAD (F, arrows). Axial FLAIR MRIs reveal typical ovoid periventricular lesions in MS (G, arrows), a peri-third ventricle hyperintense lesion in AQP4 NMOSD (H, arrow), and characteristic deep gray matter (bithalamic) hyperintense lesions in MOGAD (I, arrows). Axial postcontrast T1-weighted images show multiple enhancing lesions typical of MS (J), linear ependymal enhancement occasionally encountered with AQP4 NMOSD (K, arrow), and prominent enhancing vessels in MOGAD (L, arrows).