MRI of acute optic neuritis (ON) at the first episode : can we predict the visual outcome and the development of multiple sclerosis (MS)?

Aim: Our aim was to assess MRI findings in the acute phase of ON and their correlation with visual acuity at presentation, visual outcome (VO) and MS development, to analyze a possible correlation between lesions number and diagnosis, and to assess correlation between orbits MRI and OCT. Materials and methods: We retrospectively studied 37 patients, who presented to our Emergency Department with an ON first episode from January 2015 to January 2017. Patients underwent immediately a complete neuro-ophthalmological evaluation, blood test, CSF analysis. MRI of brain, orbits, cervical spine was executed within 7 days from ON onset. Brain MRI was classified as: normal, non-specific, suspected demyelination, lesions with dissemination in space and time. Optic nerves findings were localized in three sites (intra-orbital, canalicular and chiasmal) and classified as: normal, STIR- alteration, altered contrast enhancement. Patients underwent neuro-ophthalmological follow-up and MRI at 6 months to assess VO (complete recovery, partial recovery, deficit persistence). Another follow-up at 1 year was performed to identify MS or clinically isolated syndrome (CIS). Results: 64.8% patients received a diagnosis of MS; 35% of CIS. Lesions of the optic nerve were found in 65.8%. We observed statistically significant correlation between brain MRI pattern and diagnosis and between lesions number and diagnosis. We observed a statistically significant correlation between orbital MRI pattern and optical coherence tomography (OCT) results. MRI brain findings correlate with development of MS. MRI brain features and lesions number can predict the risk of MS conversion.