title: MRI characterization of brown adipose tissue in obese and normal-weight children.
abstract: BACKGROUND
  Brown adipose tissue (BAT) is identified in mammals as an adaptive thermogenic organ for modulation of energy expenditure and heat generation. Human BAT may be primarily composed of brown-in-white (BRITE) adipocytes and stimulation of BRITE may serve as a potential target for obesity interventions. Current imaging studies of BAT detection and characterization have been mainly limited to PET/CT. MRI is an emerging application for BAT characterization in healthy children.
  
  
  OBJECTIVE
  To exploit Dixon and diffusion-weighted MRI methods to characterize cervical-supraclavicular BAT/BRITE properties in normal-weight and obese children while accounting for pubertal status.
  
  
  METHODS
  Twenty-eight healthy children (9-15 years old) with a normal or obese body mass index participated. MRI exams were performed to characterize supraclavicular adipose tissues by measuring tissue fat percentage, T2*, tissue water mobility, and microvasculature properties. We used multivariate linear regression models to compare tissue properties between normal-weight and obese groups while accounting for pubertal status.
  
  
  RESULTS
  MRI measurements of BAT/BRITE tissues in obese children showed higher fat percentage (P < 0.0001), higher T2* (P < 0.0001), and lower diffusion coefficient (P = 0.015) compared with normal-weight children. Pubertal status was a significant covariate for the T2* measurement, with higher T2* (P = 0.0087) in pubertal children compared to prepubertal children. Perfusion measurements varied by pubertal status. Compared to normal-weight children, obese prepubertal children had lower perfusion fraction (P = 0.003) and pseudo-perfusion coefficient (P = 0.048); however, obese pubertal children had higher perfusion fraction (P = 0.02) and pseudo-perfusion coefficient (P = 0.028).
  
  
  CONCLUSIONS
  This study utilized chemical-shift Dixon MRI and diffusion-weighted MRI methods to characterize supraclavicular BAT/BRITE tissue properties. The multi-parametric evaluation revealed evidence of morphological differences in brown adipose tissues between obese and normal-weight children.
authors.affiliation: Department of Medical Imaging, Ann & Robert H. Lurie Children's Hospital of Chicago, 225 E. Chicago Ave., Box 9, Chicago, IL, 60611-2605, USA. jdeng@luriechildrens.org.|Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA. jdeng@luriechildrens.org.
authors.forename: Jie
authors.initials: J
authors.lastname: Deng
authors.affiliation: Department of Medical Imaging, Ann & Robert H. Lurie Children's Hospital of Chicago, 225 E. Chicago Ave., Box 9, Chicago, IL, 60611-2605, USA.
authors.forename: Samantha E
authors.initials: SE
authors.lastname: Schoeneman
authors.affiliation: Collaborative Research Unit, John H. Stroger, Jr. Hospital of Cook County, Chicago, IL, USA.
authors.forename: Huiyuan
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Stanley Manne Children's Research Institute, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA.|Department of Pediatrics, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
authors.forename: Soyang
authors.initials: S
authors.lastname: Kwon
authors.affiliation: Department of Medical Imaging, Ann & Robert H. Lurie Children's Hospital of Chicago, 225 E. Chicago Ave., Box 9, Chicago, IL, 60611-2605, USA.|Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
authors.forename: Cynthia K
authors.initials: CK
authors.lastname: Rigsby
authors.affiliation: Department of Medical Imaging, Ann & Robert H. Lurie Children's Hospital of Chicago, 225 E. Chicago Ave., Box 9, Chicago, IL, 60611-2605, USA.|Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
authors.forename: Richard M
authors.initials: RM
authors.lastname: Shore
authors.affiliation: Division of Endocrinology, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA.|Department of Pediatrics, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
authors.forename: Jami L
authors.initials: JL
authors.lastname: Josefson
mesh_terms: D002001:Adipose Tissue, Brown / Q000473:pathology*; D050154:Adiposity; D000293:Adolescent; D002648:Child; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D009765:Obesity / Q000473:pathology*; D063766:Pediatric Obesity / Q000473:pathology*; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
keywords: Brown adipose tissue; Brown-in-white adipocytes; Children; Magnetic resonance imaging; Obesity