title: Spatial distribution of MRI-Determined hepatic proton density fat fraction in adults with nonalcoholic fatty liver disease.
abstract: OBJECTIVE
  To describe the spatial distribution of liver fat,using MRI-estimated proton density fat fraction (PDFF), in adults with nonalcoholic fatty liver disease (NAFLD).
  
  
  METHODS
  This Investigational Review Board-approved, Health Insurance Portability and Accountability Act-compliant study prospectively enrolled 50 adults (30 women, 20 men) with biopsy-proven NAFLD. Hepatic PDFF was measured by low-flip-angle multiecho spoiled gradient-recalled-echo MRI at 3 Tesla. Three nonoverlapping regions of interest were placed within each liver segment. Statistical analyses included Pearson's correlation, multivariable linear regression, and permutation-based paired tests.
  
  
  RESULTS
  The study population's mean whole-liver PDFF was 16.1% (range: 1.6–39.6%). The mean whole-liver PDFF variability was 1.9% (range: 0.7–4.5%). Higher variability was associated with higher PDFF (r=0.34;P=0.0156). The mean PDFF was significantly higher in the right lobe than the left (16.5% versus 15.3%, P=0.0028). The mean PDFF variability was higher in the left lobe than the right (1.86% versus 1.28%; P<0.0001). Segment II had the lowest mean segmental PDFF (14.8%);segment VIII had the highest (16.7%). Segments V(0.71%) and VI (0.70%) had the lowest mean segmental PDFF variability; segment II had the highest (1.32%).
  
  
  CONCLUSIONS
  IN adult NAFLD there are small but significant differences in fat content.
authors.affiliation: Clinical MRI, Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins School of Medicine, Baltimore, Maryland, USA.
authors.forename: Susanne
authors.initials: S
authors.lastname: Bonekamp
authors.forename: An
authors.initials: A
authors.lastname: Tang
authors.forename: Arian
authors.initials: A
authors.lastname: Mashhood
authors.forename: Tanya
authors.initials: T
authors.lastname: Wolfson
authors.forename: Christopher
authors.initials: C
authors.lastname: Changchien
authors.forename: Michael S
authors.initials: MS
authors.lastname: Middleton
authors.forename: Lisa
authors.initials: L
authors.lastname: Clark
authors.forename: Anthony
authors.initials: A
authors.lastname: Gamst
authors.forename: Rohit
authors.initials: R
authors.lastname: Loomba
authors.forename: Claude B
authors.initials: CB
authors.lastname: Sirlin
mesh_terms: D050154:Adiposity; D000328:Adult; D000368:Aged; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008099:Liver / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D065626:Non-alcoholic Fatty Liver Disease / Q000473:pathology*; D011446:Prospective Studies; D011522:Protons; D055815:Young Adult
chemical_list: D011522:Protons