Quantification of liver, pancreas, kidney, and vertebral body MRI-PDFF in non-alcoholic fatty liver disease Ilkay S. Idilman, 1 Ali Tuzun, 2 Berna Savas, 3 Atilla Halil Elhan, 4 Azim Celik, 5 Ramazan Idilman, 2 Musturay Karcaaltincaba 1 1 Department of Radiology, Faculty of Medicine, Hacettepe University, 06100 Ankara, Turkey 2 Department of Gastroenterology, Faculty of Medicine, Ankara University, Ankara, Turkey 3 Department of Pathology, Faculty of Medicine, Ankara University, Ankara, Turkey 4 Department of Biostatistics, Faculty of Medicine, Ankara University, Ankara, Turkey 5 General Electric Healthcare, Istanbul, Turkey Abstract Purpose: The purpose of the present study was to determine liver, pancreas, kidney, and vertebral fat deposition in NAFLD patients by proton density fat fraction (PDFF) using magnetic resonance imaging (MRI) and to evaluate the relationships among them. Methods: A total of 41 biopsy-proven NAFLD patients underwent MRI-PDFF with IDEAL-IQ. MRI protocol included T1-independent volumetric multi-echo gradient- echo imaging with T2* correction and spectral fat modeling. The MR examinations were performed on a 1.5 HDx MRI system. MRI-PDFF measurements were obtained from liver, pancreas, renal cortex and sinus, and vertebral body. Liver biopsy specimens were retrieved from the archives and evaluated by one pathologist according to NASH CRN. Results: The median age of the patients was 47 years. The median interval between liver biopsy and MRI examina- tion was 16 days. Mean liver, pancreas, renal cortex, renal sinus, T12 and L1 vertebral body MRI-PDFFs were 18.7%, 5.7%, 1.7%, 51%, 43.2%, and 43.5%, respectively. No correlation between either liver MRI-PDFF or histological steatosis, and other organ MRI-PDFFs was observed. A good correlation between pancreas and vertebral body MRI-PDFFs, and pancreas and renal sinus MRI-PDFFs was observed. Diabetic patients had higher average pancreas MRI-PDFF compared to non- diabetics (12.2%, vs., 4.8%; P = 0.028). Conclusions: Pancreas and vertebral body MRI-PDFF is well correlated in NAFLD patients and both of them are higher in diabetic patients which may explain increased bone fractures in diabetics. MRI-PDFF can be used to demonstrate fat fractions of different organs and tissues and to understand fat metabolism. Key words: Non-alcoholic fatty liver disease—MRI- PDFF—Pancreas—Kidney—Vertebral body Non-alcoholic fatty liver disease (NAFLD) is the ex- cessive accumulation of fat in hepatocytes and affects approximately 30% of general population with an in- creasing rate [1, 2]. Although frequently benign, there are several clinical manifestations of this disease related to liver injury like non-alcoholic steatohepatitis (NASH), cirrhosis, and hepatocellular carcinoma [1–4]. Beside hepatic manifestations, associations with obesi- ty, insulin resistance (IR), type 2 diabetes mellitus, hy- pertension, hyperlipidemia, and cardiovascular disease suggest complex relationships among them. Liver biopsy remains the reference method for both con- firming the diagnosis of NAFLD and grading the dis- ease. Potential risks of liver biopsy like bleeding, perforation, and even mortality [5] motivated the in- vestigators to find a non-invasive method for diagnosis and grading of NAFLD. Magnetic resonance spectroscopy (MRS) is the most accepted method for quantitative analysis of the liver fat [6–8]. However, it is not available for routine clinical practice because of technical difficulties in both perfor- mance and evaluation [7, 9]. A recent MR technique—MRI- estimated proton density fat fraction (MRI-PDFF)—gives Correspondence to: Musturay Karcaaltincaba; email: musturayk@yahoo. com ª Springer Science+Business Media New York 2015 Abdominal Imaging Abdom Imaging (2015) DOI: 10.1007/s00261-015-0385-0