title: Between-centre variability versus variability over time in DXA whole body measurements evaluated using a whole body phantom.
abstract: This study aimed to compare the variability of whole body measurements, using dual energy X-ray absorptiometry (DXA), among geographically distinct centres versus that over time in a given centre. A Hologic-designed 28 kg modular whole body phantom was used, including high density polyethylene, gray polyvinylchloride and aluminium. It was scanned on seven Hologic QDR 4500 DXA devices, located in seven centres and was also repeatedly (n=18) scanned in the reference centre, over a time span of 5 months. The mean between-centre coefficient of variation (CV) ranged from 2.0 (lean mass) to 5.6% (fat mass) while the mean within-centre CV ranged from 0.3 (total mass) to 4.7% (total area). Between-centre variability compared well with within-centre variability for total area, bone mineral content and bone mineral density, but was significantly higher for fat (p<0.001), lean (p<0.005) and total mass (p<0.001). Our results suggest that, even when using the same device, the between-centre variability remains a matter of concern, particularly where body composition is concerned.
authors.affiliation: Department of Radiology, AZ-VUB, Vrije Universiteit Brussel, Laarbeeklaan 101, 1090 Brussels, Belgium. olivia.louis@az.vub.ac.be
authors.forename: Olivia
authors.initials: O
authors.lastname: Louis
authors.forename: Siska
authors.initials: S
authors.lastname: Verlinde
authors.forename: Muriel
authors.initials: M
authors.lastname: Thomas
authors.forename: Jean
authors.initials: J
authors.lastname: De Schepper
mesh_terms: D015502:Absorptiometry, Photon / Q000379:methods / Q000706:statistics & numerical data; D001823:Body Composition / Q000502:physiology; D015519:Bone Density / Q000502:physiology; D019047:Phantoms, Imaging / Q000706:statistics & numerical data*; D015203:Reproducibility of Results; D013997:Time Factors; D051598:Whole Body Imaging / Q000379:methods* / Q000706:statistics & numerical data*