Assessing the risk of early multiple sclerosis in patients with clinicallyisolated syndromes: the role of a follow up MRI

Objectives-With increasing evidence that permanent tissue damage occurs ear ly in the course of multiple sclerosis, it is important that treatment tria ls include patients in the earliest stages of the disease. For many patient s with multiple sclerosis the first presentation is a clinically isolated s yndrome. Not all patients with a clinically isolated syndrome develop multi ple sclerosis, however, and treatment of all such patients would be unwarra nted. A single abnormal brain MRI identifies patients at a higher risk for the early development of multiple sclerosis, but current criteria are limit ed by either poor specificity (T2 lesions) or sensitivity (contrast enhanci ng lesions). The aim of the study was to assess the positive predictive val ue, sensitivity, and specificity of MRI indices for the development of mult iple sclerosis after 1 year from two MRI examinations obtained 3 months apa rt. Methods-MRT examinations were performed in 68 patients with a clinically is olated syndrome, with a clinical assessment after 1 year. Results-Contrast enhancing lesions at both time points were the most predic tive indices for developing multiple sclerosis (positive predictive value 7 0%) but had low sensitivity (39%). The combination of T2 lesions at baselin e with new T2 lesions at follow up had the best overall positive predictive value (53%), sensitivity (83%), and specificity (76%). In patients with T2 lesions at baseline, the presence or absence of new T2 lesions at follow u p significantly altered the risk of multiple sclerosis within 1 year (55% a nd 5% respectively, p<0.001). Multiple sclerosis also developed in 10% of p atients with a normal baseline MRI. Conclusions-Serial imaging in patients with clinically isolated syndromes i mproved the positive predictive value, sensitivity, and specificity of MRI for the development of early multiple sclerosis and also identified patient s at a lower risk of early multiple sclerosis than would have been expected from their abnormal baseline MRI. Selection of patients with clinically is olated syndromes for therapeutic intervention or clinical trials may benefi t from serial MRI, to target those at greatest risk of early development of multiple sclerosis.