The introduction of the McDonald criteria has enabled earlier diagnosis of multiple sclerosis (MS). However, even with the 2010 revised criteria, nearly 50 % of patients remain classified as “possible MS” following the first MRI. The present study aimed to demonstrate that time to MS diagnosis could be shorter than 2010 revised criteria, and established after a single early MRI in most patients with the association of the symptomatic lesion and at least one suggestive asymptomatic lesion. We also evaluated the short-term predictive capacity of an individual suggestive lesion on disease activity. We analyzed initial MRI results from 146 patients with MS from a multicenter retrospective study. Visualization of the symptomatic lesion was used as a primary criterion. Secondary criteria included one suggestive lesion (SL) aspect or topography on MRI, or one non-specific lesion associated with positive CSF. The proposed criteria led to a positive diagnosis of MS in 100 % of cases, from information available from the time of the first MRI for 145 patients (99.3 %). At least one SL was observed for 143 patients (97.9 %), and positive CSF for the 3 others. Compared to the McDonald criteria, the proposed criteria had 100 % sensitivity, with a significantly shorter mean time to reach a positive diagnosis. Furthermore, the simultaneous presence of corpus callosum, temporal horn, and ovoid lesions was associated with radiological or clinical activity after a year of follow-up. The proposed diagnostic criteria are easy to apply, have a good sensitivity, and allow an earlier diagnosis than the 2010 McDonald criteria. Nevertheless, prospective studies are needed to establish specificity and to confirm these findings. © 2015, Springer-Verlag Berlin Heidelberg.