Bone and Muscle Parameters of the Tibia: Agreement Between the XCT 2000 and XCT 3000 Instruments

Burrows, Melonie; Cooper, David M.L.; Liu, Danmei; McKay, Heather A.

doi:10.1016/j.jocd.2008.09.005

« Previous Next »Journal of Clinical Densitometry
Volume 12, Issue 2 , Pages 186-194, April 2009

Bone and Muscle Parameters of the Tibia: Agreement Between the XCT 2000 and XCT 3000 Instruments

Melonie Burrows
- Department of Orthopaedics, University of British Columbia, British Columbia, Canada
- Centre for Hip Health and Mobility, University of British Columbia, British Columbia, Canada
- Address correspondence to: Dr. Melonie Burrows, PhD, Department of Orthopaedics and Engineering, Faculty of Medicine, University of British Columbia, Centre for Hip Health and Mobility, Vancouver Coastal Health Research Institute, Room 589 Research Pavilion, 828 West 10th Avenue, Vancouver, BC V5Z 1L8, Canada.
David M.L. Cooper
- Department of Anatomy and Cell Biology, University of Saskatchewan, Saskatchewan, Canada
Danmei Liu
- Department of Orthopaedics, University of British Columbia, British Columbia, Canada
- Centre for Hip Health and Mobility, University of British Columbia, British Columbia, Canada
Heather A. McKay
- Department of Orthopaedics, University of British Columbia, British Columbia, Canada
- Centre for Hip Health and Mobility, University of British Columbia, British Columbia, Canada

Received 18 August 2008; received in revised form 30 September 2008; accepted 30 September 2008. published online 12 November 2008.

Abstract

Peripheral quantitative computed tomography is a valuable tool to assess bone in children across growth, with long-term studies capturing nuances missed in cross-sectional studies. As children grow, a change from XCT 2000 to a XCT 3000 may be required to accommodate the increasing size of the lower limbs. We examined the precision and agreement between the Stratec XCT 2000 and 3000 on selected bone and muscle parameters. Twenty-eight participants (mean±SD; age 27.5±6.5yr) underwent scans at the distal (8%), mid (50%), and proximal (66%) tibia sites, to assess total bone area, total bone density, and trabecular density (8% site); and total bone area, cortical area, cortical density (CoD), polar strength-strain index, and muscle cross-sectional area (50% and 66% sites). Outcomes between instruments were highly correlated; r=0.90–0.99 for CoD across sites, with r=0.97–0.99 for all other measures. Bland and Altman plots showed excellent agreement between instruments for all variables. Regression indicated no significant relationship between instrument and size of measurement (p>0.05). Coefficients of variation were lower than previously reported (0.4–2.4%). For longitudinal studies, the XCT 3000 can replace the XCT 2000 with minimal influence on bone and muscle parameters.