MRI Results From the Optic Neuritis Treatment Trial

The Optic Neuritis Treatment Trial (ONTT), a multicenter study funded by the National Eye Institute, Is designed to determine the efficacy of corticosteroid treatment in optic neuritis. On entry into the ONTI, all patients undergo a standardized neurologic examination and magnetic resonance imaging (MRI) of the brain. On the basis of the clinical examination alone, by the Poser criteria the first 361 patients have been classified as definite multiple sclerosis in 5%, probable in 8%, possible in 20%, and no MS in 67%. Initial readings of the MRI scans at each clinic have classified the scans as abnormal in 59%: 93% abnormal in the definite MS group, 93% in the probable group, 66% In the possible group, and 49% in the noMS group. Each scan also is being graded by a central reading unit. The grading system and the results of these readings will be presented.