B Academy of Molecular Imaging, 2009 Published Online: 6 October 2009 DOI: 10.1007/s11307-009-0258-4 Mol Imaging Biol (2010) 12:233Y239 BRIEF ARTICLE Quantitative Assessment of the Hepatic Metabolic Volume Product in Patients with Diffuse Hepatic Steatosis and Normal Controls Through Use of FDG-PET and MR Imaging: A Novel Concept Gonca G. Bural, 1 Drew A. Torigian, 1 Anne Burke, 1 Mohamed Houseni, 1 Khaled Alkhawaldeh, 1 Andrew Cucchiara, 1 Sandip Basu, 1,2 Abass Alavi 1 1 Division of Nuclear Medicine, Department of Radiology, Hospital of the University of Pennsylvania, 3400 Spruce Street, 110 Donner Bldg., Philadelphia( PA 19104, USA 2 Radiation Medicine Centre (BARC), Tata Memorial Hospital Annexe, Parel, Bombay 400012, India Abstract Aims and Objectives: The aim of this study was to compare hepatic standardized uptake values (SUVs) and hepatic metabolic volumetric products (HMVP) between patients of diffuse hepatic steatosis and control subjects with normal livers. Materials and Methods: Twenty-seven subjects were included in the study (13 men and 14 women; age range, 34–72 years). All had 18F-2-fluoro-2-D-deoxyglucose-positron emission tomography (FDG-PET) and magnetic resonance imaging (MRI) scans with an interscan interval of 0–5 months. Twelve of 27 subjects had diffuse hepatic steatosis on MRI. The remaining 15 were selected as age-matched controls based on normal liver parenchyma on MRI. Mean and maximum hepatic SUVs were calculated for both patient groups on FDG-PET images. Hepatic volumes were measured from MRI. HMVP in each subject was subsequently calculated by multiplication of hepatic volume by mean hepatic SUV. HMVPs as well as mean and maximum hepatic SUVs were compared between the two study groups. Results: HMVPs, mean hepatic SUVs, and maximum hepatic SUVs were greater (statistically significant, p G 0.05) in subjects with diffuse hepatic steatosis compared to those in the control group. Conclusion: The increase in HMVP is the result of increased hepatic metabolic activity likely related to the diffuse hepatic steatosis. The active inflammatory process related to the diffuse hepatic steatosis is the probable explanation for the increase in hepatic metabolic activity on FDG-PET study. Key words: Hepatic steatosis, Fatty liver, Liver, FDG-PET, MRI, Hepatic metabolic volumetric product (HMVP) Introduction N onalcoholic fatty liver disease (NAFLD) is an increas- ingly recognized cause of liver-related morbidity and mortality [1]. NAFLD encompasses a spectrum of disease ranging from bland steatosis to nonalcoholic steatohepatitis (NASH). NAFLD is the accumulation of triglycerides in hepatocytes, necrosis of hepatocytes, and development of inflammation and fibrosis [2] that may ultimately lead to hepatic cirrhosis and liver failure. It can develop secondary Correspondence to: Abass Alavi; e-mail: alavi@rad.upenn.edu