Microstructural Parameters of Bone Evaluated Using HR-pQCT Correlate with the DXA-Derived Cortical Index and the Trabecular Bone Score in a Cohort of Randomly Selected Premenopausal Women

Abstract

Background Areal bone mineral density is predictive for fracture risk. Microstructural bone parameters evaluated at the appendicular skeleton by high-resolution peripheral quantitative computed tomography (HR-pQCT) display differences between healthy patients and fracture patients. With the simple geometry of the cortex at the distal tibial diaphysis, a cortical index of the tibia combining material and mechanical properties correlated highly with bone strength ex vivo. The trabecular bone score derived from the scan of the lumbar spine by dual-energy X-ray absorptiometry (DXA) correlated ex vivo with the micro architectural parameters. It is unknown if these microstructural correlations could be made in healthy premenopausal women. Methods Randomly selected women between 20–40 years of age were examined by DXA and HR-pQCT at the standard regions of interest and at customized sub regions to focus on cortical and trabecular parameters of strength separately. For cortical strength, at the distal tibia the volumetric cortical index was calculated directly from HR-pQCT and the areal cortical index was derived from the DXA scan using a Canny threshold-based tool. For trabecular strength, the trabecular bone score was calculated based on the DXA scan of the lumbar spine and was compared with the corresponding parameters derived from the HR-pQCT measurements at radius and tibia. Results Seventy-two healthy women were included (average age 33.8 years, average BMI 23.2 kg/m2). The areal cortical index correlated highly with the volumetric cortical index at the distal tibia (R = 0.798). The trabecular bone score correlated moderately with the microstructural parameters of the trabecular bone. Conclusion This study in randomly selected premenopausal women demonstrated that microstructural parameters of the bone evaluated by HR-pQCT correlated with the DXA derived parameters of skeletal regions containing predominantly cortical or cancellous bone. Whether these indexes are suitable for better predictions of the fracture risk deserves further investigation.

Association between bone indices assessed by DXA, HR-pQCT and QCT scans in post-menopausal women

“…A study by Silva et al [13] investigated these correlations in 115 pre-and postmenopausal women, and in partial accordance with our results the authors demonstrated weak to moderate associations with TBS. The results were further supported by Popp et al [29] in 72 healthy pre-menopausal women, showing similar correlations. As TBS reflects the heterogeneity of trabecular structures of lumbar vertebrae, it is taken into account in the descriptions of its correlations that it should correlate more strongly with trabecular indices than with cortical parameters.…”

Trabecular bone score: perspectives of an imaging technology coming of age

“…More recently, the association of TBS with HRpQCT indices was investigated in 72 healthy premenopausal women (mean age 33.8 years) (21). TBS was associated with trabecular volumetric BMD (r = 0.49 to 0.57), Tb.N (r = 0.43 to 0.58), Conn.D (r = 0.43 to 0.46), and Tb.Sp (r = -0.43 to -0.57), at the radius and tibia (all p < 0.01).…”

Trabecular bone score in type 1 diabetes—a cross-sectional study

“…TBS measurements are based on experimental variograms of two-dimensional (2D) projections of existing DXA assessments and-when used in addition to BMD measurements taken at the same anatomical site-help to predict bone quality and osteoporotic fractures independently of clinical risk factors [9]. It has recently been demonstrated that in premenopausal women, the microstructural parameters of bone, as evaluated by highresolution peripheral quantitative computed tomography (HR-pQCT), correlate with TBS [10]. In general, higher TBS reflect a denser bone with a higher resistance to fracture.…”