Peripheral quantitative computed tomography at the distal radius: cross-calibration between two scanners

Area of Science:

• Musculoskeletal research
• Biomedical engineering
• Radiology

Background:

• Peripheral quantitative computed tomography (pQCT) is crucial for studying muscle-bone interactions.
• Established pQCT reference ranges exist for younger populations using the Stratec XCT 2000 scanner.
• The older Stratec XCT 900 scanner remains in widespread use, necessitating cross-calibration with newer data.

Purpose of the Study:

• To cross-calibrate the Stratec XCT 900 and XCT 2000 pQCT scanners.
• To enable the use of existing reference data with scans from the XCT 900.
• To establish conversion factors for distal radius measurements between the two scanner models.

Main Methods:

• Analysis of distal radii from 19 healthy adult subjects (aged 21-59).
• Measurements performed on both XCT 900 and XCT 2000 scanners at the '4% site'.
• Comparison of cross-sectional area, total and trabecular bone mineral density (BMD), total bone mineral content (BMC), and polar Strength-Strain Index (SSI) using linear regression.

Main Results:

• High correlation coefficients were found between the XCT 900 and XCT 2000 for key bone parameters.
• Specific correlations: 0.82 (area), 0.81 (total BMD), 0.97 (trabecular BMD), 0.99 (BMC), and 0.86 (polar SSI).
• Intercept and slope values derived from regression analysis provide calibration factors.

Conclusions:

• The study provides essential data for converting pQCT measurements between the Stratec XCT 900 and XCT 2000 scanners.
• This facilitates the consistent application of reference ranges across different scanner versions.
• Accurate cross-calibration ensures reliable bone health assessments in musculoskeletal research.