Comparison of the Performance of an Optimized 3D EPI SWI Sequence and a Non-EPI QSM SWI Sequence in Detecting the Central Vein Sign in Patients With Multiple Sclerosis

Patients who have agreed to participate in the study will complete the MRI protocol as part of routine care, to which four additional 20-minute sequences will be added. MRI of routine care in the context of MS includes at least the following sequences: * 3D T1 TFE (2 minutes) * T2 TSE (2 minutes) * 3D FLAIR (3 minutes) * SWI EPI 0.6 iso (7 minutes) The sequences added by the search are: * SWI non EPI QSM 6 echo (10 minutes) * SWI EPI in resolution equivalent to non-EPI SWI (3 minutes) * SWI EPI to TR equivalent to SWI non EPI (6 minutes) These sequences will be acquired before or after the injection of gadolinium (if present in the examination of routine care). For examinations carried out with injection, the order of carrying out the 4 post-injection SWI sequences will be random.