Non-invasive assessment of metabolic dysfunction-associated fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) affects an estimated one-quarter of the global adult population and has become one of the leading causes of end-stage liver disease and hepatocellular carcinoma with increased liver-related and overall morbidity and mortality. The new term, metabolic dysfunction-associated fatty liver disease (MAFLD), has a set of positive diagnostic criteria and has been shown to have better clinical utility, but it has yet to be universally adopted. This review addresses the non-invasive tests for MAFLD and is based mostly on studies on NAFLD patients, as the MAFLD term is relatively new and there are limited studies on non-invasive tests based on this new term, while a large body of research work on non-invasive tests has accumulated in the literature for NAFLD. This review focuses on blood-based biomarkers and scores for the assessment of hepatic steatosis, non-alcoholic steatohepatitis (NASH), and fibrosis, and two of the most widely studied imaging biomarkers, namely vibration-controlled transient elastography and magnetic resonance imaging. Fibrotic NASH has become a diagnostic target of interest and novel serum biomarkers and scores incorporating imaging biomarker for diagnosis of fibrotic NASH are emerging. Nonetheless, the degree of liver fibrosis remains the key predictor of liver-related morbidity and mortality in patients with MAFLD. A multitude of non-invasive biomarkers and scores have been studied for the detection of liver fibrosis, including use of sequential non-invasive tests for risk stratification of advanced liver fibrosis. In addition, this review will explore the utility of the non-invasive tests for prognostication and for monitoring of treatment response.