title: Quantification of liver proton-density fat fraction in 7.1T preclinical MR systems: Impact of the fitting technique.
abstract: To investigate the feasibility of estimating the proton-density fat fraction (PDFF) using a 7.1T magnetic resonance imaging (MRI) system and to compare the accuracy of liver fat quantification using different fitting approaches.
  
  
  
  Fourteen leptin-deficient ob/ob mice and eight intact controls were examined in a 7.1T animal scanner using a 3D six-echo chemical shift-encoded pulse sequence. Confounder-corrected PDFF was calculated using magnitude (magnitude data alone) and combined fitting (complex and magnitude data). Differences between fitting techniques were compared using Bland-Altman analysis. In addition, PDFFs derived with both reconstructions were correlated with histopathological fat content and triglyceride mass fraction using linear regression analysis.
  
  
  
  The PDFFs determined with the use of both reconstructions correlated very strongly (r = 0.91). However, small mean bias between reconstructions demonstrated divergent results (3.9%; confidence interval [CI] 2.7-5.1%). For both reconstructions, there was linear correlation with histopathology (combined fitting: r = 0.61; magnitude fitting: r = 0.64) and triglyceride content (combined fitting: r = 0.79; magnitude fitting: r = 0.70).
  
  
  
  Liver fat quantification using the PDFF derived from MRI performed at 7.1T is feasible. PDFF has strong correlations with histopathologically determined fat and with triglyceride content. However, small differences between PDFF reconstruction techniques may impair the robustness and reliability of the biomarker at 7.1T. J. Magn. Reson. Imaging 2016;44:1425-1431.
authors.affiliation: Department of Radiology and Neuroradiology, University of Greifswald, Greifswald, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Mahlke
authors.affiliation: Department of Radiology, University of Wisconsin, Madison, Wisconsin, USA.
authors.forename: Diego
authors.initials: D
authors.lastname: Hernando
authors.affiliation: Department of Radiology and Neuroradiology, University of Greifswald, Greifswald, Germany.
authors.forename: Christina
authors.initials: C
authors.lastname: Jahn
authors.affiliation: Department of Pathology, University of Greifswald, Greifswald, Germany.
authors.forename: Antonio
authors.initials: A
authors.lastname: Cigliano
authors.affiliation: Institute of Community Medicine, University of Greifswald, Greifswald, Germany.
authors.forename: Till
authors.initials: T
authors.lastname: Ittermann
authors.affiliation: Institute of Animal Nutrition, University of Veterinary Medicine, Hannover, Germany.
authors.forename: Anne
authors.initials: A
authors.lastname: Mössler
authors.affiliation: Department of Radiology and Neuroradiology, University of Greifswald, Greifswald, Germany.
authors.forename: Marie-Luise
authors.initials: ML
authors.lastname: Kromrey
authors.affiliation: Department of Immunology, University of Greifswald, Greifswald, Germany.
authors.forename: Grazyna
authors.initials: G
authors.lastname: Domaska
authors.affiliation: Department of Radiology, University of Wisconsin, Madison, Wisconsin, USA.|Departments of Medical Physics, Biomedical Engineering, Medicine and Emergency Medicine, University of Wisconsin, Madison, Wisconsin, USA.
authors.forename: Scott B
authors.initials: SB
authors.lastname: Reeder
authors.affiliation: Department of Radiology and Neuroradiology, University of Greifswald, Greifswald, Germany.
authors.forename: Jens-Peter
authors.initials: JP
authors.lastname: Kühn
mesh_terms: D000465:Algorithms; D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D003720:Densitometry / Q000379:methods*; D005223:Fats / Q000378:metabolism*; D005240:Feasibility Studies; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008099:Liver / Q000378:metabolism* / Q000502:physiology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D057054:Molecular Imaging / Q000379:methods; D009716:Numerical Analysis, Computer-Assisted; D011522:Protons; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D015415:Biomarkers; D005223:Fats; D011522:Protons
keywords: chemical shift imaging; liver fat; proton-density fat fraction; ultra-high-field MRI