Multiple sclerosis (MS) is the first non-traumatic cause of disability in young people, responsible for physical but also cognitive deficits. MS is an inflammatory demyelinating and degenerative disease of the central nervous system. Recently, MRI technics have demonstrated their sensibility to the different processes involved in MS. Particularly, MRI has evidenced that the pathological process of MS is not restricted to the macroscopic lesions of the white matter but also involves the normal appearing white and grey matter. In the normal appearing brain tissue, demyelination, neuronal suffering and neuronal loss have been evidenced. Moreover, MRI has demonstrated the existence of brain functional reorganization processes that may limit the clinical expression of pathological injuries. Despite these important findings, the pathological underpinnings of irreversible disability are largely unknown. The present project aims to depict the main determinants of physical but also cognitive disability in patients with MS. To do this, a longitudinal study including 70 patients with MS using different MRI markers known to be sensitive to the different pathological aspects of MS will be performed. The relationships between these markers and the progression of disability will be assessed. Identification of the main pathological underpinnings of irreversible disability of MS will provide the most relevant therapeutic targets.

Inclusion Criteria:

• Major patient,
• Patient affiliated to a health insurance plan
• Patient having signed free and informed consent after receiving detailed, understandable and honest information,
• Patient with multiple sclerosis according to the criteria of Polman 2010

Exclusion Criteria:

• Patients with the usual contraindications to MRI (pace-maker, agitation, metal splinters, claustrophobia etc.)
• Patients at risk of non-compliance on examination: impaired understanding, confusion, involuntary movements, poor tolerance of prolonged supine
• Patients with known allergy to gadolinium
• Patients with renal insufficiency
• Patients unable to give their consent: disorders of the comprehension, disturbances of vigilance, confusion ...
• Pregnant and breastfeeding woman
• Patients with a history of neurological or psychiatric pathology
• Patients under guardianship or curatorship