This is a single centre prospective open-label, non-randomised pilot study whose aim is to identify MRI parameters to better evaluate inflammation and liver fibrosis and thus, in the near future, to avoid the need for liver biopsy.

To achieve this:

• The MRI study will be completed by adding two sequences: Measurement of T1 and multiecho T2*. The other data will be extracted from usual sequences.
• Part of the histological samples will be used for the weighted levels of fat and iron, and for the lipidomic study.
• Usual blood samples will be completed by samples for the serum library

Inclusion Criteria:

• Patients who have been informed about the research
• Patients with national health insurance cover
• Patients who are overweight (BMI > 25) or have type 2 diabetes suggesting a disturbance of hepatic enzymes (ASAT < 8 times normal values and ALAT > twice normal values) after a complete hepatopathy assessment
• Obese patients with a hepatic anomaly (steatosis) revealed by imaging or biological assessment (ASAT < 8 times normal values and ALAT > twice normal values) who are eligible for bariatric surgery and a preoperative liver MRI examination.

Exclusion Criteria:

• Non-corrected coagulation disorder.
• Patients aged over 80 years
• Patients aged less than 18 years
• Patients without legal protection
• Patients with a contra-indication for MRI (Pacemaker, intraocular metallic foreign body, weight>150kg)
• Patients without national health insurance cover

Overweight patients or patients with type 2 diabetes or obese patients (who present a liver anomaly and should undergo bariatric surgery)