title: Effect of weight loss on magnetic resonance imaging estimation of liver fat and volume in patients with nonalcoholic steatohepatitis.
abstract: OBJECTIVE
  Little is known about how weight loss affects magnetic resonance imaging (MRI) of liver fat and volume or liver histology in patients with nonalcoholic steatohepatitis (NASH). We measured changes in liver fat and liver volume associated with weight loss by using an advanced MRI method.
  
  
  METHODS
  We analyzed data collected from a previous randomized controlled trial in which 43 adult patients with biopsy-proven NASH underwent clinical evaluation, biochemical tests, and MRI and liver biopsy analyses at the start of the study and after 24 weeks. We compared data between patients who did and did not have at least 5% decrease in body mass index (BMI) during the study period.
  
  
  RESULTS
  Ten of 43 patients had at least a 5% decrease in BMI during the study period. These patients had a significant decrease in liver fat, which was based on MRI proton density fat fraction estimates (18.3% ± 7.6% to 13.6% ± 13.6%, P = .03), a relative 25.5% reduction. They also had a significant decrease in liver volume (5.3%). However, no significant changes in levels of alanine aminotransferase or aspartate aminotransferase were observed with weight loss. Thirty-three patients without at least 5% decrease in BMI had insignificant increases in estimated liver fat fraction and liver volume.
  
  
  CONCLUSIONS
  A reduction in BMI of at least 5% is associated with significant decrease in liver fat and volume in patients with biopsy-proven NASH. These data should be considered in assessing effect size in studies of patients with nonalcoholic fatty liver disease or obesity that use MRI-estimated liver fat and volume as end points.
authors.affiliation: Division of Internal Medicine, Department of Medicine, University of California San Diego Health System, La Jolla, California.
authors.forename: Niraj S
authors.initials: NS
authors.lastname: Patel
authors.affiliation: Division of Gastroenterology, Department of Medicine, University of California San Diego Health System, La Jolla, California.
authors.forename: Iliana
authors.initials: I
authors.lastname: Doycheva
authors.affiliation: Department of Pathology, University of California San Diego Health System, La Jolla, California.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Peterson
authors.affiliation: Liver Imaging Group, Department of Radiology, University of California San Diego Health System, La Jolla, California.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Hooker
authors.affiliation: Department of Surgery, University of California San Diego Health System, La Jolla, California.
authors.forename: Tatiana
authors.initials: T
authors.lastname: Kisselva
authors.affiliation: Division of Gastroenterology, Department of Medicine, University of California San Diego Health System, La Jolla, California.
authors.forename: Bernd
authors.initials: B
authors.lastname: Schnabl
authors.affiliation: Division of Gastroenterology, Department of Medicine, University of California San Diego Health System, La Jolla, California; Department of Surgery, University of California San Diego Health System, La Jolla, California.
authors.forename: Ekihiro
authors.initials: E
authors.lastname: Seki
authors.affiliation: Liver Imaging Group, Department of Radiology, University of California San Diego Health System, La Jolla, California.
authors.forename: Claude B
authors.initials: CB
authors.lastname: Sirlin
authors.affiliation: Division of Gastroenterology, Department of Medicine, University of California San Diego Health System, La Jolla, California; Division of Epidemiology, Department of Family and Preventive Medicine, University of California San Diego Health System, La Jolla, California. Electronic address: roloomba@ucsd.edu.
authors.forename: Rohit
authors.initials: R
authors.lastname: Loomba
mesh_terms: D000328:Adult; D000368:Aged; D001706:Biopsy; D015992:Body Mass Index; D005223:Fats; D005260:Female; D006651:Histocytochemistry; D006801:Humans; D008099:Liver / Q000000981:diagnostic imaging / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D065626:Non-alcoholic Fatty Liver Disease / Q000150:complications / Q000473:pathology*; D011859:Radiography; D016032:Randomized Controlled Trials as Topic; D015431:Weight Loss
chemical_list: D005223:Fats
keywords: Biomarker; Noninvasive; Response to Treatment; Steatosis