title: Reproducibility of peripheral quantitative computed tomography measurements at the radius and tibia in healthy pre- and postmenopausal women.
abstract: OBJECTIVE
  The objectives of this study were to utilise the XCT-2000 pQCT scanner to determine the mean values and the reproducibility of in vivo total, trabecular, and cortical volumetric bone measurements at distal and diaphyseal sites of the radius and the tibia, as well as calf muscle and subcutaneous fat areas, in healthy pre- and postmenopausal women.
  
  
  METHODS
  Twenty-nine women (14 premenopausal and 15 postmenopausal) were recruited to participate in this study. Distal and diaphyseal sites of the radius (at 4% and 20% of the length of the radius) and tibia (at 4%, 38%, and 66% of the length of the tibia) were examined.
  
  
  RESULTS
  The root mean square coefficient of variation for measurements at the distal tibia gave the most favorable reproducibility values for total (1.5%) and trabecular (1.6%) density, whereas the diaphyseal tibia showed the most favorable reproducibility value for cortical density (0.3%). The root mean square coefficients of variation for measurements of muscle and fat cross-sectional areas at the calf were 0.6% and 0.7%, respectively. At the distal tibia, the mean values for total (P < .05) and trabecular (P < .01) density were significantly lower in postmenopausal women than in premenopausal women.
  
  
  CONCLUSIONS
  The data presented here indicate that XCT-2000 pQCT scans at the tibia provide highly reproducible measurements of total, cortical, and trabecular bone as well as muscle and fat cross-sectional areas. Furthermore, significant differences in volumetric bone measurements between healthy pre- and postmenopausal women were evident only at the distal tibia, suggesting that this site warrants further study.
authors.affiliation: Department of Nuclear Medicine, Hamilton Health Sciences, McMaster University, Hamilton, Ontario, Canada. szabok2@mcmaster.ca
authors.forename: Kristina A
authors.initials: KA
authors.lastname: Szabo
authors.forename: Colin E
authors.initials: CE
authors.lastname: Webber
authors.forename: Christopher
authors.initials: C
authors.lastname: Gordon
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Adachi
authors.forename: Richard
authors.initials: R
authors.lastname: Tozer
authors.forename: Alexandra
authors.initials: A
authors.lastname: Papaioannou
mesh_terms: D000328:Adult; D015519:Bone Density; D005260:Female; D006801:Humans; D008875:Middle Aged; D017698:Postmenopause; D017697:Premenopause; D011884:Radius / Q000000981:diagnostic imaging*; D015203:Reproducibility of Results; D013977:Tibia / Q000473:pathology*; D014057:Tomography, X-Ray Computed