Cerebral magnetic resonance imaging (MRI) could provide evidence for dissemination in space by revealing clinically silent lesions and so contribute to a better assessment of MS risk. We examined 24 patients with isolated optic neuritis: 19 females, 7 males, age range 18-51 years, median age 26 years, 17 with symptoms on left eye, 5 on right eye, 1 on both eyes