Bone imaging modality precision and agreement between DXA, pQCT, and HR-pQCT

Area of Science:

• Bone densitometry
• Medical imaging
• Orthopedics

Background:

• Accurate precision error quantification is vital for monitoring body composition and musculoskeletal health.
• Understanding agreement between peripheral quantitative computed tomography (pQCT) and second-generation high-resolution pQCT (HR-pQCT) is needed.

Purpose of the Study:

• To determine the precision, agreement, and associations between bone variables assessed using DXA, pQCT, and second-generation HR-pQCT.

Main Methods:

• Thirty older adults underwent DXA scans (total hip, lumbar spine, whole body) and pQCT/HR-pQCT scans at radius and tibia.
• Precision errors were calculated using root-mean-squared coefficients of variation (%CVRMS).
• Agreement was assessed using Bland-Altman plots; correlations and linear regression explored relationships and bias.

Main Results:

• Precision errors were generally low across all modalities (DXA: 0.55–1.6%; pQCT: 0.40–4.8%; HR-pQCT: 0.13–30.7%).
• Significant systematic bias was found between pQCT and HR-pQCT volumetric BMD (vBMD) estimates (p<.001), but no proportional bias.
• Bone density and strength measures from pQCT and HR-pQCT were strongly correlated (p<.05).

Conclusions:

• DXA, pQCT, and HR-pQCT demonstrate acceptable precision for assessing bone variables.
• Despite systematic bias, pQCT and HR-pQCT vBMD estimates are strongly related, indicating potential for similar fracture prediction.
• Bone density and strength measures from these modalities are not interchangeable but are highly correlated.