Inclusion Criteria:  Clinically suspected or proven nonalcoholic fatty liver disease (NAFLD) Patients who are scheduled hepatic parenchymal biopsy for suspected liver disease or hepatectomy for living donor liver donation aged ≥ 18 years who are willing and able to complete all procedures  Exclusion Criteria:  excessive alcohol consumption within 2 years (40g/day for men, 20g/day for women) clinical, laboratory, or histologic evidence of a liver disease other than NAFLD, including viral hepatitis, autoimmune hepatitis, or genetic or acquired disorders use of steatogenic or hepatotoxic medication evidence of decompensated liver disease history of liver surgery any other condition believed by investigator to affect a patients' compliance, or completion of the study