title: Dual-energy X-ray absorptiometry registers bone mineral in the liver.
abstract: OBJECTIVE
  To analyse the difference in bone mineral content (BMC) between the left and right trunk generally obtained by dual-energy X-ray absorptiometry (DXA) by creating identical images over the liver region and the contralateral side.
  
  
  METHODS
  Fifty-four patients were selected at random from 1,722 subjects examined by DXA because of osteoporosis. Another five patients were selected who had been followed for osteoporosis by repeated DXA two to five times at intervals from 2 to 36 months. One healthy volunteer was followed for one day by means of DXA total body measurements. All protocols were analysed with respect to BMC, fat mass (FM) and lean tissue mass (LTM) of the imaged trunk and liver.
  
  
  RESULTS
  BMC of the right trunk exceeded that of the left trunk in 78% of the investigated subjects. The right (liver) image dominated in all 81 investigations calculated from 60 subjects. There were intraindividual short- and longterm variations between repeated DXA examinations. The amounts of FM and LTM were distributed symmetrically between the right and left trunk.
  
  
  CONCLUSIONS
  DXA registers BMC in the liver, which explains the general dominance of the right trunk. The absorption over the liver region varies in the same individual in repeated measurements at intervals of hours to months.
authors.affiliation: Department of Hospital Physics, Söder Hospital, Stockholm, Sweden. markos.koufakis@fysik.sos.sll.se
authors.forename: M
authors.initials: M
authors.lastname: Koufakis
authors.forename: B
authors.initials: B
authors.lastname: Söderborg
authors.forename: G
authors.initials: G
authors.lastname: Kallner
authors.forename: A
authors.initials: A
authors.lastname: Magi
authors.forename: G
authors.initials: G
authors.lastname: Svensson
mesh_terms: D015502:Absorptiometry, Photon / Q000379:methods; D000368:Aged; D001823:Body Composition; D015519:Bone Density; D005260:Female; D006801:Humans; D008099:Liver / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D010024:Osteoporosis / Q000000981:diagnostic imaging / Q000503:physiopathology; D012044:Regression Analysis