Comparison of Xtreme CT and DXA Bone Densitometry

Dual-energy x-ray absorptiometry (DXA) is currently the most widely used tool for determining bone density. However, most experts consider DXA an imperfect and intermediate technology. DXA is subject to artifact from arthritis and body composition, and also cannot account for geometric or material properties of bone which are also important components of bone strength.

Xtreme CT (high-resolution peripheral quantitative computed tomography, HR-pQCT) is a new technology with dramatically improved spatial resolution. It is able to define bones' cortical and trabecular surfaces in a three-dimensional manner, and therefore provides information on bone microarchitecture as well as bone density. As such, it may provide new information about characteristics of bone strength.

The purpose of this study is to compare Xtreme CT to DXA measurements of bone density, and also to generate a normative database of healthy young adults. This cross-sectional study involves a single visit where both Xtreme CT and DXA measurements will be obtained for a single time-point. This normative database will allow us to generate clinically relevant comparisons between the two imaging technologies.