RESUMO
Hepatic steatosis can be observed in chronic liver diseases of different etiologies. The main predisposing factors for hepatic steatosis include chronic viral hepatitis， cholestatic liver disease， alcoholic liver disease， and nonalcoholic fatty liver disease. Simple fatty liver disease is the initial manifestation of hepatic steatosis， followed by steatohepatitis， liver fibrosis， liver cirrhosis， and even hepatocellular carcinoma. With the development of medical imaging technology， magnetic resonance imaging-proton density fat fraction （MRI-PDFF） has been widely used in the diagnosis of fatty liver disease （FLD） in clinical practice. MRI-PDFF is gradually becoming the gold standard for the noninvasive diagnosis of FLD due to its high accuracy and good repeatability. This article reviews the clinical application of MRI-PDFF in liver fat quantification and related research advances.