Quantitative Ultrasound Techniques for Diagnosis of Nonalcoholic Steatohepatitis

Nonalcoholic fatty liver disease is the most common liver disease in Western countries, due in large part to its association with type 2 diabetes and obesity. The more advanced form of this disease is known as nonalcoholic steatohepatitis (NASH). If left untreated, NASH can evolve to cirrhosis, the late stage of fibrosis. Once cirrhosis is established, patients are at increased risk of developing gastrointestinal bleeding, liver cancer and liver failure that may require transplantation. A liver biopsy is currently needed to diagnose the severity of fatty liver disease but this is usually not indicated in asymptomatic patients. This procedure requires the insertion of a needle inside the liver to remove a small piece of tissue for examination under microscope. Liver biopsy is an invasive procedure with a small risk of major complications such as bleeding in 0.5% of cases. It is also affected by sub-optimal sampling leading to diagnostic errors Ultrasound is optimum for screening patients with or without symptoms because it is a safe and widely available technology to scan the whole liver. Members of our team have developed Advanced ultrasound techniques that provide unique information not possible with state-of-the-art techniques. Unlike liver biopsy, these techniques would be applicable even in asymptomatic patients because it is non-invasive. This research proposal proposes a novel approach for diagnosis of NASH and will be the first study to measure individual components of NASH (fat, inflammation and fibrosis) with quantitative ultrasound (QUS) scores. This study is timely because NASH is the second leading cause of liver transplantation in North America and is predicted to become the leading indication in the near future.