page_title: Non-alcoholic fatty liver disease
section_title: Imaging
hierarchical_section_title: Non-alcoholic fatty liver disease / Diagnosis / Imaging
caption_attribution_description: English: Multiecho MR images in a healthy liver (top row) and a liver with severe steatosis (bottom row). In the healthy liver, the signal does not vary in the different echoes. In the steatotic liver, the signal varies greatly between in and out phase echoes. Algebraic combination of these images can be used to accurately quantify liver steatosis.
context_page_description: Non-alcoholic fatty liver disease, also known as metabolic associated fatty liver disease, is excessive fat build-up in the liver without another clear cause such as alcohol use. There are two types; non-alcoholic fatty liver and non-alcoholic steatohepatitis, with the latter also including liver inflammation. Non-alcoholic fatty liver disease is less dangerous than NASH and usually does not progress to NASH or liver cirrhosis. When NAFLD does progress to NASH, it may eventually lead to complications such as cirrhosis, liver cancer, liver failure, or cardiovascular disease.
  Obesity and type 2 diabetes are strong risk factors for NAFLD. Other risks include being overweight, metabolic syndrome, a diet high in fructose, and older age. NAFLD and alcoholic liver disease are types of fatty liver disease. Obtaining a sample of the liver after excluding other potential causes of fatty liver can confirm the diagnosis.
  Treatment for NAFLD is weight loss by dietary changes and exercise. There is tentative evidence for pioglitazone and vitamin E; bariatric surgery can improve or resolve severe cases. Those with NASH have a 2.6% increased risk of dying per year.
context_section_description: A liver ultrasound scan or magnetic resonance imaging (MRI) can diagnose steatosis, but not fibrosis and confirmation of early cirrhosis detection by ultrasound by other diagnostic methods is recommended. The European Association for the Study of the Liver (EASL) recommends screening for steatosis whenever NAFLD is suspected as this is a strong predictor of the disease evolution and predicts future type 2 diabetes, cardiovascular events, and hypertension. These non-invasive methods can be used for NAFLD screening but are not accepted as a substitute for liver biopsy in NAFLD nor NASH clinical trials, as only a liver biopsy can define liver pathology.
  CT scans and MRIs are more accurate in detecting cirrhosis than conventional ultrasound. Transient elastography is recommended for the initial assessment of liver fibrosis and cirrhosis and helps to predict complications and prognosis, but the interpretation of results is carefully weighed in the presence of limiting factors, such as steatosis, high BMI, lower degrees of hepatic fibrosis and narrow spaces between the ribs (intercostal spaces). However, transient elastography can fail for people with pre-hepatic portal hypertension. Transient elastography is not considered to be a replacement for liver biopsy.
  Magnetic resonance elastography (MRE) is an emerging method that can accurately assess hepatic fibrosis and is recommended by the APASL. MRE possesses a good sensitivity to quantify hepatic fat and excellent accuracy to detect fibrosis in NAFLD regardless of BMI and inflammation and is suggested as a more reliable alternative to diagnose NAFLD and its progression to NASH compared to ultrasound and blood tests.
caption: MRI of a healthy liver (top row) and one with severe steatosis (bottom row)
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