title: Feasibility of and agreement between MR imaging and spectroscopic estimation of hepatic proton density fat fraction in children with known or suspected nonalcoholic fatty liver disease.
abstract: OBJECTIVE
  To assess feasibility of and agreement between magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) for estimating hepatic proton density fat fraction (PDFF) in children with known or suspected nonalcoholic fatty liver disease (NAFLD).
  
  
  METHODS
  Children were included in this study from two previous research studies in each of which three MRI and three MRS acquisitions were obtained. Sequence acceptability, and MRI- and MRS-estimated PDFF were evaluated. Agreement of MRI- with MRS-estimated hepatic PDFF was assessed by linear regression and Bland-Altman analysis. Age, sex, BMI-Z score, acquisition time, and artifact score effects on MRI- and MRS-estimated PDFF agreement were assessed by multiple linear regression.
  
  
  RESULTS
  Eighty-six children (61 boys and 25 girls) were included in this study. Slope and intercept from regressing MRS-PDFF on MRI-PDFF were 0.969 and 1.591%, respectively, and the Bland-Altman bias and 95% limits of agreement were 1.17% ± 2.61%. MRI motion artifact score was higher in boys than girls (by 0.21, p = 0.021). Higher BMI-Z score was associated with lower agreement between MRS and MRI (p = 0.045).
  
  
  CONCLUSIONS
  Hepatic PDFF estimation by both MRI and MRS is feasible, and MRI- and MRS-estimated PDFF agree closely in children with known or suspected NAFLD.
authors.affiliation: Liver Imaging Group, Department of Radiology, School of Medicine, University of California, San Diego, San Diego, CA, USA.
authors.forename: Emil
authors.initials: E
authors.lastname: Achmad
authors.affiliation: Liver Imaging Group, Department of Radiology, School of Medicine, University of California, San Diego, San Diego, CA, USA.|Department of Radiology and Advanced Imaging Research Center, UT Southwestern School of Medicine, Dallas, TX, USA.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yokoo
authors.affiliation: Liver Imaging Group, Department of Radiology, School of Medicine, University of California, San Diego, San Diego, CA, USA.
authors.forename: Gavin
authors.initials: G
authors.lastname: Hamilton
authors.affiliation: Liver Imaging Group, Department of Radiology, School of Medicine, University of California, San Diego, San Diego, CA, USA.
authors.forename: Elhamy R
authors.initials: ER
authors.lastname: Heba
authors.affiliation: Liver Imaging Group, Department of Radiology, School of Medicine, University of California, San Diego, San Diego, CA, USA.
authors.forename: Jonathan C
authors.initials: JC
authors.lastname: Hooker
authors.affiliation: Liver Imaging Group, Department of Radiology, School of Medicine, University of California, San Diego, San Diego, CA, USA.
authors.forename: Christopher
authors.initials: C
authors.lastname: Changchien
authors.affiliation: Liver Imaging Group, Department of Radiology, School of Medicine, University of California, San Diego, San Diego, CA, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Schroeder
authors.affiliation: Computational and Applied Statistics Laboratory (CASL), San Diego Supercomputing Center (SDSC), University of California, San Diego, San Diego, CA, USA.
authors.forename: Tanya
authors.initials: T
authors.lastname: Wolfson
authors.affiliation: Computational and Applied Statistics Laboratory (CASL), San Diego Supercomputing Center (SDSC), University of California, San Diego, San Diego, CA, USA.
authors.forename: Anthony
authors.initials: A
authors.lastname: Gamst
authors.affiliation: Liver Imaging Group, Department of Radiology, School of Medicine, University of California, San Diego, San Diego, CA, USA.|Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, School of Medicine, University of California, San Diego, San Diego, CA, USA.|Department of Gastroenterology, Rady Children's Hospital San Diego, San Diego, CA, USA.
authors.forename: Jeffrey B
authors.initials: JB
authors.lastname: Schwimmer
authors.affiliation: Department of Pediatrics, Columbia University, New York, NY, USA.
authors.forename: Joel E
authors.initials: JE
authors.lastname: Lavine
authors.affiliation: Liver Imaging Group, Department of Radiology, School of Medicine, University of California, San Diego, San Diego, CA, USA.
authors.forename: Claude B
authors.initials: CB
authors.lastname: Sirlin
authors.affiliation: Liver Imaging Group, Department of Radiology, School of Medicine, University of California, San Diego, San Diego, CA, USA. msm@ucsd.edu.|UCSD Department of Radiology, UCSD MRI Institute, 410 West Dickinson Street, San Diego, CA, 92103-8749, USA. msm@ucsd.edu.
authors.forename: Michael S
authors.initials: MS
authors.lastname: Middleton
mesh_terms: D000293:Adolescent; D016477:Artifacts; D002648:Child; D003430:Cross-Sectional Studies; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008099:Liver / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D065626:Non-alcoholic Fatty Liver Disease / Q000473:pathology*; D011522:Protons; D015203:Reproducibility of Results; D012189:Retrospective Studies
chemical_list: D011522:Protons
keywords: MRI; MRS; NAFLD; PDFF; Proton density fat fraction; Steatosis