Longitudinally Extensive Optic Neuritis Distinguishes Neuromyelitis Optica from Multiple Sclerosis

The anterior visual pathway is morphologically and physiologically part of the central nervous system, and its response to injury is similar. Demyelinating and inflammatory processes may affect the AVP and are typically disruptive of the local blood brain barrier, as is frequently noted in optic neuritis. One report showed that enhancement length did not distinguish optic neuritis between neuromyelitis optica (NMO) and multiple sclerosis (MS) when multiple cases were averaged. However, the specificity for longitudinally extensive enhancement of the AVP to differentiate optic neuritis among NMO, MS, and sarcoidosis has not been previously reported. Radiographic analysis can help distinguish abnormal processes affecting the optic nerves and anterior visual pathways (AVP). We hypothesize that length of pathologic AVP contrast enhancement can be a predictor of etiologic diagnosis in optic neuritis.