The main objective is to compare the accuracy of transient elastography taking into account liver steatosis determined by MRI, to liver biopsy for the diagnosis of liver fibrosis ≥F2 in patient with NAFLD.

No alcoholic fatty liver disease (NAFLD) is induced by an abnormal build up of fat in the liver. It can induce liver damage, namely fibrosis, which leads to cirrhosis and an increased risk of liver cancer. The diagnosis of liver fibrosis is thus critical to identify patients at risk.

Liver biopsy is the gold standard for the diagnosis of liver fibrosis. However this invasive test is expensive and has a significant morbidity.

To avoid this others non invasive test have been developed to assess steatosis and fibrosis of the liver :

• Magnetic Resonance Imaging can quantify liver steatosis accurately.
• Transient elastography (Fibroscan®) is approved for the diagnosis of fibrosis in chronic hepatitis C. However results in NAFLD were disappointing. Further, steatosis by heightening liver elasticity is thought to be the cause of these poor results.
• Several biological tests or score are also approved in chronic hepatitis C, but not in NAFLD.

The hypothesis driving this study is that by accounting for liver steatosis through the mean of MRI, we could more accurately interpret transient elastography value to accurately diagnose the severity of liver fibrosis.

Inclusion Criteria:

• Patients older than 18 years old

• For which a liver biopsy is indicated for NAFLD according to current guidelines

• Presenting with at least one of the metabolic syndrome criteria:

  • BMI > 25 kg/m² and/or Waist circumference ≥ à 94cm for men / ≥ à 80cm for women
  • Fasting glucose > or = to 5,6 mmol/L or diabetes / or lowering glucose treatment
  • Blood pressure ≥ 130/85 mmHg / or treatment
  • Triglycerides ≥ than 1,7 mmol/L
  • HDL-C ≤ than 1 mmol/L (men), ≤ 1,3 mmol/L (women) /or lipid lowering treatment

• Affiliated to medical care insurance

• Having signed informed consent for participating in the study

Exclusion Criteria:

• Associated other chronic liver disease : infectious, auto immune, genetic
• Alcohol consumption higher than 21 standard unit per week for men, or 14 standard unit for women;
• Steatosis inducing treatment: steroids, amiodarone, methotrexate, tamoxifen
• History of bariatric surgery
• Contra indication to MRI (pace maker, metallic foreign body, claustrophobia)
• Persons subject to major legal protection (safeguarding justice, guardianship, trusteeship), persons deprived of liberty.

Patients with NAFLD