Predictions of Vertebral Strength From Quantitative Measures of the Intra-Vertebral Heterogeneity in Density

Current fracture risk estimates for the spine are based on average measures of bone mineral density (BMD) in the vertebral centrum. However, these measures of BMD explain only ∼60% of the variance in vertebral strength [1] and do not discriminate well between fracture and non-fracture cohorts [2]. These limitations of average BMD are likely due to the heterogeneous distribution of bone tissue throughout the vertebra. The density and architecture of vertebral trabecular bone vary as a function of position in the centrum [3]; moreover, these spatial variations have been shown to vary substantially among individuals and with age [3].