title: Comparison of brown and white adipose tissues in infants and children with chemical-shift-encoded water-fat MRI.
abstract: OBJECTIVE
  To compare fat-signal fractions (FFs) and T2* values between brown (BAT) and white (WAT) adipose tissue located within the supraclavicular fossa and subcutaneous depots, respectively.
  
  
  METHODS
  Twelve infants and 39 children were studied. Children were divided into lean and overweight/obese subgroups. Chemical-shift-encoded water-fat magnetic resonance imaging (MRI) was used to quantify FFs and T2* metrics in the supraclavicular and adjacent subcutaneous adipose tissue depots. Linear regression and t-tests were performed.
  
  
  RESULTS
  Infants had lower supraclavicular FFs than children (P < 0.01) but T2* values were similar (P = 0.5). Lean children exhibited lower supraclavicular FFs and T2* values than overweight children (P < 0.01). In each individual infant and child, supraclavicular FFs were consistently lower than adjacent subcutaneous FFs. Supraclavicular T2* values were consistently lower than subcutaneous T2* values in children, but not in infants. FFs in both depots were positively correlated with age and weight in infants (P < 0.01). In children, they were correlated with weight and body mass index (BMI) (P < 0.01), but not age. Correlations between T2* and anthropometric variables existed in children (P < 0.01), but were absent in infants.
  
  
  CONCLUSIONS
  Cross-sectional comparisons suggest variations in FF and T2* values in the supraclavicular and subcutaneous depots of infants and children, which are potentially indicative of physiological differences in adipose tissue fat content, amount, and metabolic activity.
authors: Department of Radiology, Children's Hospital Los Angeles, Los Angeles, California, USA.
authors: Houchun H
authors: HH
authors: Hu
authors: Larry
authors: L
authors: Yin
authors: Patricia C
authors: PC
authors: Aggabao
authors: Thomas G
authors: TG
authors: Perkins
authors: Jonathan M
authors: JM
authors: Chia
authors: Vicente
authors: V
authors: Gilsanz
mesh_terms: D002001:Adipose Tissue, Brown / Q000033:anatomy & histology*; D052436:Adipose Tissue, White / Q000033:anatomy & histology*; D000293:Adolescent; D000886:Anthropometry; D001823:Body Composition; D015992:Body Mass Index; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D016014:Linear Models; D008279:Magnetic Resonance Imaging; D008297:Male; D009765:Obesity; D050177:Overweight; D050151:Subcutaneous Fat / Q000033:anatomy & histology; D014867:Water / Q000737:chemistry; D055815:Young Adult
chemical_list: D014867:Water
keywords: T2* relaxation; brown adipose tissue; children; fat-signal fraction; water-fat MRI; white adipose tissue