Globally, nonalcoholic associated fatty liver (NAFLD) is the predominant chronic liver disease, and it correlates to metabolic syndrome and type 2 diabetes, leading to cardiac and cerebral arteriosclerosis. In 2020, metabolic associated fatty liver disease (MAFLD) was newly defined to clarify the pathogenic mechanisms of this disease and to better guide clinical treatment. We hypothesized that with MAFLD, previously contradictory imaging results could be better explained. Liver MRS and FDG PET imaging were conducted simultaneously on an integrated PET/MR platform, which improved data accuracy. The study also analyzed whether the liver could be used as a reference tissue for PET imaging.