title: Associations between histologic features of nonalcoholic fatty liver disease (NAFLD) and quantitative diffusion-weighted MRI measurements in adults.
abstract: OBJECTIVE
  To investigate in adults the associations between histologic features of nonalcoholic fatty liver disease (NAFLD) and quantitative measures derived from diffusion-weighted imaging (DWI).
  
  
  METHODS
  Eighty-nine adults undergoing standard-of-care liver biopsy for NAFLD were recruited for DWI. Biopsies were scored for histologic features of NAFLD. DWI was performed using b-values of 0, 100, and 500 s/mm(2) . Images were reconstructed using either conventional magnitude averaging (CMA) or a method to address bulk motion artifacts (Beta*LogNormal, BLN). The apparent diffusion coefficient (ADC) and the diffusivity (D) and perfusion fraction (F) of the intravoxel incoherent motion (IVIM) model were measured in the right hepatic lobe using both reconstructions. Associations between histologic features and DWI-derived measures were tested statistically with several methods including multiple linear regression.
  
  
  RESULTS
  Using CMA and BLN reconstructions, respectively, the means (and ranges) were 1.7 (1.1-3.5) and 1.4 (1.0-3.2) × 10(-3) mm(2) /s for ADC, 1.1 (0.84-1.4) and 0.84 (0.53-1.1) × 10(-3) mm(2) /s for D, and 17 and 18 (2.3-35)% for F. For both reconstruction methods, D decreased with steatosis and F decreased with fibrosis (P < 0.05). ADC was not independently associated with any histologic feature.
  
  
  CONCLUSIONS
  Steatosis and fibrosis have significant independent effects on D and F in adults undergoing biopsy for NAFLD.
authors.affiliation: Liver Imaging Group, Department of Radiology, University of California - San Diego, San Diego, California, USA.
authors.forename: Paul
authors.initials: P
authors.lastname: Murphy
authors.affiliation: Liver Imaging Group, Department of Radiology, University of California - San Diego, San Diego, California, USA.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Hooker
authors.affiliation: NAFLD Translational Research Unit, Division of Gastroenterology, Department of Medicine, University of California - San Diego, San Diego, California, USA.
authors.forename: Brandon
authors.initials: B
authors.lastname: Ang
authors.affiliation: Computational and Applied Statistics Lab, San Diego Supercomputing Center, San Diego, California, USA.
authors.forename: Tanya
authors.initials: T
authors.lastname: Wolfson
authors.affiliation: Computational and Applied Statistics Lab, San Diego Supercomputing Center, San Diego, California, USA.
authors.forename: Anthony
authors.initials: A
authors.lastname: Gamst
authors.affiliation: Liver Imaging Group, Department of Radiology, University of California - San Diego, San Diego, California, USA.
authors.forename: Mark
authors.initials: M
authors.lastname: Bydder
authors.affiliation: Liver Imaging Group, Department of Radiology, University of California - San Diego, San Diego, California, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Middleton
authors.affiliation: Western Washington Pathology, Tacoma, Washington, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Peterson
authors.affiliation: Pacific Rim Pathology, San Diego, California, USA.
authors.forename: Cynthia
authors.initials: C
authors.lastname: Behling
authors.affiliation: NAFLD Translational Research Unit, Division of Gastroenterology, Department of Medicine, University of California - San Diego, San Diego, California, USA.|Division of Epidemiology, Department of Family and Preventative Medicine, University of California - San Diego, San Diego, California, USA.
authors.forename: Rohit
authors.initials: R
authors.lastname: Loomba
authors.affiliation: Liver Imaging Group, Department of Radiology, University of California - San Diego, San Diego, California, USA.
authors.forename: Claude
authors.initials: C
authors.lastname: Sirlin
mesh_terms: D000328:Adult; D000368:Aged; D001706:Biopsy; D003430:Cross-Sectional Studies; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008297:Male; D008875:Middle Aged; D065626:Non-alcoholic Fatty Liver Disease / Q000473:pathology*; D011446:Prospective Studies
keywords: DWI; IVIM; NAFLD; NASH; diffusion; liver