The non-alcoholic fatty liver disease (NAFLD) represents the most common cause of liver disease in the western world. It can progress from steatosis to non-alcoholic steatohepatitis (NASH), and then onto cirrhosis where there is a concomitant risk of developing hepatocellular carcinoma (HCC). The prevalence of hepatic steatosis is high, ranging from 16 to 31% in the general population, up to 80% in the obese populationand up to 96% in severely obese patients.

Liver biopsy (LB) has traditionally been regarded as the gold standard for the assessment of patients with NAFLD, although it has several limitations. LB has a potential sampling error, is an invasive and often painful procedure.

The natural history of patients with NAFLD is generally determined by the extent of liver fibrosis, hence non-invasive assessment of fibrosis with FibroScan® is often sufficient. For patients with proven NASH, changes in hepatic steatosis and serum ALT levels may provide information on the patient's course and/or response to treatment.

Several clinical studies have shown the benefit of measuring hepatic stiffness with the FibroScan® machine using the M+ probe. The ability to identify significant fibrosis and cirrhosis has been demonstrated in normal and overweight patients affected with chronic hepatitis B and C, biliary diseases, alcohol related liver disease (ALD) and NAFLD.

Recently, Echosens has also developed a novel ultrasonic controlled attenuation parameter (CAP) designed to quantify hepatic steatosis using a process based on vibration controlled transient elastography (VCTE™). Studies comparing CAP with liver biopsies in multi-aetiology cases and patients with Hepatitis C Virus (HCV) have shown that there is a good correlation between steatosis assessed histologically and using CAP.

The main objective of this prospective study is to evaluate the diagnosis accuracy of the Controlled attenuation Parameter (CAP) measured by FibroScan® (either with M+ or XL+)in patients with NAFLD to assess liver steatosis using biopsy as a reference.

The study involves adults' patients with suspected NAFLD scheduled to have a liver biopsy within 2 weeks of fibroscan examination and followed by the Hepatology service of four centers in United Kingdom.

Approximately 450 patients (of which 350 will be evaluable) will be enrolled in this study: Around 100 patients will be measured with the M+ probe and around 250 with the XL+ probe.

The inclusion period is from 18 to 24 months. Starting date: January 2014. End of recruitment: June 2017. The duration of the study for a patient is from 1 to 7 days, depending to the exams calendar.

Inclusion Criteria:

• Patients must be at least 18 years of age
• Patients must be able to give written informed consent
• Patients with suspected NAFLD
• Patients scheduled to have a liver biopsy within 2 weeks of Fibroscan examination
• HBsAg negative, Anti-HCV negative, HCV-RNA negative, HBV-DNA negative

Exclusion Criteria:

• Unable or unwilling to provide written informed consent
• Patients with ascites
• Pregnant women
• Patients with any active implantable medical device (such as pacemaker or defibrillator)
• Patients who have had a liver transplant
• Patients with cardiac failure and/or significant valvular disease
• Patients with hematochromatosis
• Refusal to undergo a liver biopsy and/or blood test
• Alcohol consumption above recommended limits (>14 units/week for women and >21 units/week for men)
• Confirmed diagnosis of active malignancy, or other terminal disease
• Patient participation in another clinical trial within the preceding 30 days