The objective of this study is to describe the change in the percentage of fat in the lumbar spine.

The study of the distribution of bone marrow adiposity is little known in subjects who did not have pathology likely to alter the fat content of the vertebrae. Or that fat content is potentially a reflection of brittle bones (osteoporosis, for example), and deserves to be known because it can be used to normalize the lipid fraction values with respect to age or from the level (L1 , L2, L3, L4 or L5) of the vertebra being studied.

Inclusion Criteria:

• Consecutive patients who underwent MRI of the lumbar spine with Sagittal sequenceT1, T2 STIR and IDEAL, good quality, in a clinical setting type back pain, spondylitis research, radicular syndrome ...
• Examinations conducted between 2014 and 2015 on the same equipment
• Major patient
• Having formulated their non-opposition

Exclusion Criteria:

• Previous history of neoplastic disease
• Vertebral Fracture
• Pathology reaching the vertebral body detectable by MRI (disc lesion with rearrangements of the endplates (MODIC)
• Inflammation,
• Bone tumor,
• fracture
• Refusal of participation

Patients who had an MRI of the lumbar spine in a context that justified (back pain, spondylitis research, radicular syndrome) having no corporeal spinal lesion at MRI examination.