Classification of nonalcoholic fatty liver disease

NAFLD was detected by an abdominal high-resolution B-mode topographic ultrasound system (ACUSON X300, Siemens, Germany) by two well-trained examiners. The fitness status and laboratory test outcomes of the patients were not revealed to the examiners. NAFLD was divided into three types: mild, moderate and severe based on the Chinese Ultrasonic Grading Criteria of NAFLD published in 2003, as follows [42]. Mild fatty liver: the intrahepatic echo is enhanced, and the boundary of the hepatic vessels and diaphragm muscle can be seen; moderate fatty liver: the intrahepatic echo is moderately increased, and the appearance of intrahepatic ducts or diaphragm muscle is slightly attenuated; severe fatty liver: the intrahepatic echo is significantly increased, and the intrahepatic duct, diaphragm muscle, or posterior right lobe is poorly visible or invisible.