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Bone and muscle parameters of the tibia: agreement between the XCT 2000 and XCT 3000 instruments
Melonie Burrows1, David M L Cooper, Danmei Liu
1Department of Orthopaedics, Centre for Hip Health and Mobility, Vancouver Coastal Health Research Institute, University of British Columbia, Vancouver, British Columbia, Canada. melonie.burrows@ubc.ca
Insights
The Stratec XCT 3000 can replace the XCT 2000 for longitudinal bone and muscle studies in children. Both devices show excellent agreement and high correlation for key bone and muscle parameters.
Area of Science:
- Orthopedics and Sports Medicine
- Pediatric Bone Health
- Imaging Technology
Background:
- Peripheral quantitative computed tomography (pQCT) is crucial for assessing pediatric bone development.
- Longitudinal studies require reliable and consistent imaging methods.
- Advancements in pQCT technology, like the Stratec XCT 3000, necessitate validation against older models such as the XCT 2000.
Purpose of the Study:
- To evaluate the precision and agreement between the Stratec XCT 2000 and XCT 3000 pQCT scanners.
- To determine if the XCT 3000 can be used interchangeably with the XCT 2000 in longitudinal pediatric studies.
- To assess bone and muscle parameters using both devices.
Main Methods:
- Twenty-eight adult participants underwent pQCT scans at multiple tibial sites (distal, mid, proximal) using both XCT 2000 and XCT 3000.
- Evaluated parameters included total bone area, total bone density, trabecular density, cortical area, cortical density (CoD), polar strength-strain index, and muscle cross-sectional area.
- Statistical analysis included correlation, Bland and Altman plots, and regression to assess agreement and precision.
Main Results:
- High correlations (r=0.90-0.99) were observed between the XCT 2000 and XCT 3000 for all measured bone and muscle parameters.
- Bland and Altman analysis demonstrated excellent agreement between the two devices across all sites and variables.
- Coefficients of variation were low (0.4-2.4%), indicating high precision, and no significant instrument-device interaction with measurement size was found.
Conclusions:
- The Stratec XCT 3000 shows high precision and excellent agreement with the XCT 2000 for assessing bone and muscle parameters.
- The XCT 3000 is a suitable replacement for the XCT 2000 in longitudinal studies, ensuring minimal disruption to data continuity.
- This validation supports the continued use of pQCT in pediatric research and clinical practice with technological advancements.
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+/-6.5 yr) 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.
