Objective:To investigate the optic magnetic resonance imaging (MRI) findings in patients with neuromyelitis optica (NMO).Methods: Patients with suspected NMO underwent brain,spinal cord and the optic MRI scanning and imaging analysis;41 patients who met the latest diagnosis criteria of NMO were enrolled in the present study and were the followed up.The MRI characteristics of the optic nerves at different stages were analyzed,and 32 healthy volunteers served as control.The results of visual evoked potential (VEP) were analyzed retrospectively to investigate whether there was difference between the positive rate of VEP and MRI findings.Results: MRI imaging showed that the shape of bilateral optic nerves was straight in healthy volunteers,and just a moiety of the optic showed slightly higher signal.In NMO patients,signals of the optic at unilateral or bilateral side were obviously intensified and appeared like railway lines,which was different from healthy volunteers.In acute phase,22 (53.7%) patients were accompanied by optic swelling and/or distortion,31 (76.5%) had enhanced T1WI,and 17 (41.5%) had high-point signal in the optic nerve.In the remission stage,15 (36.6%) had their optic nerves atrophied,thinned or even distorted on unilateral and/or bilateral side.At the end of the study,35 (80.5%) showed high-point signal in the optic nerve.The overall sensitivity of MRI was 94.6%,but in acute phase the sensitivity was just 43.6%,indicating the sensitivity of MRI was time-dependent and was not as sensitive as VEP.Conclusion: MRI can clearly demonstrate the changes at different stages of optic nerve atherosclerosis in NMO patients.MRI may be the first choice for diagnosis of NMO.