Brain structural and functional MRI alterations and their predictive value for the visual outcome at 3 years in clinically isolated optic neuritis.

ABSTRACT

AIM: To investigate the structural and functional magnetic resonance imaging (MRI) alterations and their clinical significance for predicting visual outcomes at 3 years in clinically isolated optic neuritis (CION). MATERIALS AND METHODS: Forty-three CION patients and 44 matched healthy controls (HC) underwent a three dimensional (3D) T1-weighted and resting-state functional MRI using a 3 T MRI system. Grey-matter volume (GMV) and functional MRI measures were compared among HC and CION patients with good and poor outcomes. The correlations between MRI measures and visual outcomes were investigated, and a binary logistic regression model was performed to predict the visual outcome. RESULTS: CION patients with good and poor outcomes showed similar patterns of decreased GMV and increased functional MRI activities compared to HC. Compared to patients with good visual recovery, CION patients with poor visual recovery showed significantly reduced GMV in the insula and superior temporal gyrus (STG), decreased amplitude of low-frequency fluctuation (ALFF) in the inferior frontal gyrus (IFG), and increased functional activities in the middle frontal gyrus (MFG) and middle temporal gyrus (MTG). Binary logistic regression analysis predicted poor visual recovery, including decreased GMV in the bilateral insula (right insula odds ratio [OR] = 17.46, p<0.001; left insula OR=10.538, p=0.001; respectively) and STG (OR=16.551, p<0.001) and increased ALFF (OR=17.148, p<0.001) and regional homogeneity (OR=10.068, p=0.002) in the left MTG. CONCLUSION: CION patients showed decreased GMV and increased functional activities predominantly located in visual- and cognition-related areas. Decreased GMV and increased ALFF or regional homogeneity in the high-order visual regions (insula, STG, and MTG) are promising imaging markers predicting poor visual outcomes at the 3-year follow-up.