title: Noninvasive measurements of body composition and body water via quantitative magnetic resonance, deuterium water, and dual-energy x-ray absorptiometry in awake and sedated dogs.
abstract: OBJECTIVE
  To compare quantitative magnetic resonance (QMR), dual-energy x-ray absorptiometry (DXA), and deuterium oxide (D2O) methods for measurement of total body water (TBW), lean body mass (LBM), and fat mass (FM) in healthy dogs and to assess QMR accuracy.
  
  
  METHODS
  58 Beagles (9 months to 11.5 years old).
  
  
  METHODS
  QMR scans were performed on awake dogs. A D2O tracer was administered (100 mg/kg, PO) immediately before dogs were sedated, which was followed by a second QMR or DXA scan. Jugular blood samples were collected before and 120 minutes after D2O administration.
  
  
  RESULTS
  TBW, LBM, and FM determined via QMR were not significantly different between awake or sedated dogs, and means differed by only 2.0%, 2.2%, and 4.3%, respectively. Compared with results for D2O dilution, QMR significantly underestimated TBW (10.2%), LBM (13.4%), and FM (15.4%). Similarly, DXA underestimated LBM (7.3%) and FM (8.4%). A significant relationship was detected between FM measured via D2O dilution and QMR (r(2) > 0.89) or DXA (r(2) > 0.88). Even though means of TBW and LBM differed significantly between D2O dilution and QMR or DXA, values were highly related (r(2) > 0.92).
  
  
  CONCLUSIONS
  QMR was useful for determining body composition in dogs and can be used to safely and rapidly acquire accurate data without the need for sedation or anesthesia. These benefits can facilitate frequent scans, particularly in geriatric, extremely young, or ill pets. Compared with the D2O dilution method, QMR correction equations provided accurate assessment over a range of body compositions.
authors.affiliation: Nestlé Purina PetCare Basic Research Group, Nestlé Research Center, 2 Research S, St Louis, MO 63164, USA. brian.zanghi@rd.nestle.com
authors.forename: Brian M
authors.initials: BM
authors.lastname: Zanghi
authors.forename: Carolyn J
authors.initials: CJ
authors.lastname: Cupp
authors.forename: Yuanlong
authors.initials: Y
authors.lastname: Pan
authors.forename: Delphine G
authors.initials: DG
authors.lastname: Tissot-Favre
authors.forename: Norton W
authors.initials: NW
authors.lastname: Milgram
authors.forename: Tim R
authors.initials: TR
authors.lastname: Nagy
authors.forename: Howard
authors.initials: H
authors.lastname: Dobson
mesh_terms: D015502:Absorptiometry, Photon / Q000379:methods / Q000662:veterinary*; D000375:Aging; D000818:Animals; D001823:Body Composition / Q000502:physiology*; D001834:Body Water / Q000502:physiology*; D016292:Procedural Sedation / Q000662:veterinary; D003903:Deuterium; D004285:Dogs; D005260:Female; D008279:Magnetic Resonance Imaging / Q000379:methods / Q000662:veterinary*; D008297:Male; D014867:Water / Q000737:chemistry
chemical_list: D014867:Water; D003903:Deuterium