title: MR properties of brown and white adipose tissues.
abstract: OBJECTIVE
  To explore the MR signatures of brown adipose tissue (BAT) compared with white adipose tissue (WAT) using single-voxel MR spectroscopy.
  
  
  METHODS
  (1) H MR STEAM spectra were acquired from a 3 Tesla clinical whole body scanner from seven excised murine adipose tissue samples of BAT (n=4) and WAT (n=3). Spectra were acquired at multiple echo times (TEs) and inversion times (TIs) to measure the T1, T2, and T2-corrected peak areas. A theoretical triglyceride model characterized the fat in terms of number of double bonds (ndb) and number of methylene-interrupted double bonds (nmidb).
  
  
  RESULTS
  Negligible differences between WAT and BAT were seen in the T1 and T2 of fat and the T2 of water. However, the water fraction in BAT was higher (48.5%) compared with WAT (7.1%) and the T1 of water was lower in BAT (618 ms) compared with WAT (1053 ms). The fat spectrum also differed, indicating lower levels of unsaturated triglycerides in BAT (ndb=2.7, nmidb=0.7) compared with WAT (ndb=3.3, nmidb=1.0).
  
  
  CONCLUSIONS
  We have demonstrated that there are several key MR-based signatures of BAT and WAT that may allow differentiation on MR imaging.
authors.affiliation: Department of Radiology, University of California, San Diego, San Diego, California, USA.
authors.forename: Gavin
authors.initials: G
authors.lastname: Hamilton
authors.forename: Daniel L
authors.initials: DL
authors.lastname: Smith
authors.forename: Mark
authors.initials: M
authors.lastname: Bydder
authors.forename: Krishna S
authors.initials: KS
authors.lastname: Nayak
authors.forename: Houchun H
authors.initials: HH
authors.lastname: Hu
mesh_terms: D002001:Adipose Tissue, Brown / Q000473:pathology*; D052436:Adipose Tissue, White / Q000473:pathology*; D000818:Animals; D001831:Body Temperature; D001835:Body Weight; D015331:Cohort Studies; D005260:Female; D007091:Image Processing, Computer-Assisted / Q000379:methods; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D051379:Mice; D015203:Reproducibility of Results; D014867:Water / Q000737:chemistry
chemical_list: D014867:Water