<i>In Vivo</i>Assessment of Trabecular Bone Microarchitecture by High-Resolution Peripheral Quantitative Computed Tomography

Abstract

Context: Assessment of trabecular microarchitecture may enhance the prediction of fracture risk and improve monitoring of treatment response. A new high-resolution peripheral quantitative computed tomography (HR-pQCT) system permits in vivo assessment of trabecular architecture and volumetric bone mineral density (BMD) at the distal radius and tibia with a voxel size of 82 μm3. Objective and Patients: We determined the short-term reproducibility of this device by measuring 15 healthy volunteers three times each. We compared HR-pQCT measurements in 108 healthy premenopausal, 113 postmenopausal osteopenic, and 35 postmenopausal osteoporotic women. Furthermore, we compared values in postmenopausal osteopenic women with (n = 35) and without previous fracture history (n = 78). Design and Setting: We conducted a cross-sectional study in a private clinical research center. Intervention and Main Outcome Measure: We took HR-pQCT measurements of the radius and tibia. Femoral neck and spine BMD were measured in postmenopausal women by dual-energy x-ray absorptiometry. Results: Precision of HR-pQCT measurements was 0.7–1.5% for total, trabecular, and cortical densities and 2.5–4.4% for trabecular architecture. Postmenopausal women had lower density, trabecular number, and cortical thickness than premenopausal women (P < 0.001) at both radius and tibia. Osteoporotic women had lower density, cortical thickness, and increased trabecular separation than osteopenic women (P < 0.01) at both sites. Furthermore, although spine and hip BMD were similar, fractured osteopenic women had lower trabecular density and more heterogeneous trabecular distribution (P < 0.02) at the radius compared with unfractured osteopenic women. Conclusion: HR-pQCT appears promising to assess bone density and microarchitecture at peripheral sites in terms of reproducibility and ability to detect age- and disease-related changes.