age between 18 and 50 years.

health coverage.

any form of ms defined by mc donald's criteria (2005).

patients having shown an enhanced plaque on a less than six month mri examination.

patients with an immunomodulating therapy like natalizumab (tysabri) and intravenous immunosuppressive therapies. other therapies will not be excluded from this study. for patients treated by systemic corticotherapy, a one-month delay will be necessary before a mri examination.

cerebral microangiopathy (diabetes, arterial hypertension, vascularitis…)

patient with classical mri contraindication like pace-maker, cardiac valvulosis, claustrophobia, allergy to contrast agent …

pregnancy or pregnancy desire.

patient with a low creatinine clearance <60 ml/mn