Inclusion Criteria:
- Age ≥ 18 years at the time of agreement
- Free subject, without guardianship or curatorship or subordination
- Patients benefiting from a Social Security scheme or benefiting from it through a third party
- Informed consent signed by the patient after clear and complete information about the study
Exclusion Criteria:
- 3T MRI contraindications (pacemaker, cochlear implant, metallic splinter, etc)
- History of neurological pathology
- Previous operations involving the central nervous system (spinal surgery, neurological surgery, etc.)
- Current pathology or treatment that may interfere with the CSF or subarachnoid spaces (CSF dysregulation, disc herniation, hydrocephalus, Chiari malformation, etc.)
- Concurrent participation in another clinical research study
- Persons not covered by Social Security or not covered by Social Security through a third party
- Persons benefiting from enhanced protection, namely minors, persons deprived of their liberty by a judicial or administrative decision, adults under legal protection
- Pregnant or breastfeeding women, women of childbearing age who do not have effective contraception (hormonal/mechanical: oral, injectable, transcutaneous, implantable, intrauterine device, or surgical: tubal ligation, hysterectomy, total oophorectomy)
Exclusion criteria during the study:
- Discovery of a contraindication to 3T MRI (pacemaker, cochlear implant, metallic splinter, etc)