Clinical strategy of diagnosing and following patients with nonalcoholic fatty liver disease based on invasive and noninvasive methods

Nonalcoholic fatty liver disease (NAFLD) is an important cause of chronic liver injury in many countries. The incidence of NAFLD is rising rapidly in both adults and children, because of the currently ongoing epidemics of obesity and type 2 diabetes. Notably, histological liver fibrosis is recognized as the main predictive factor for the overall long-term outcome of NAFLD, including cardiovascular disease and liver-related mortality. Thus, staging of liver fibrosis is essential in determining the prognosis and optimal treatment for patients with NAFLD and in guiding surveillance for the development of hepatocellular carcinoma (HCC). Whereas liver biopsy remains the gold standard for staging liver fibrosis, it is impossible to enforce liver biopsy in all patients with NAFLD. Noninvasive biological markers, scoring systems and noninvasive modalities are increasingly being developed and investigated to evaluate fibrosis stage of NAFLD patients. This review will highlight recent studies on the diagnosis and staging of NAFLD based on invasive (liver biopsy) or noninvasive (biomarker, scoring systems, US-based elastography and MR elastography) methods.