Relation between image-based assessment of distal radius trabecular structure and compressive strength.

OBJECTIVE: To investigate the degree to which an image-based assessment of trabecular bone structure can predict bone strength. METHODS: Transaxial high-resolution magnetic resonance imaging (MRI) images and peripheral quantitative computed tomography (pQCT) images were obtained for a set of 9 isolated radii. Trabecular bone was segmented from fat, and indices relating to the connectivity of the bone network and the size of the marrow space were derived. Bone mineral density was also assessed in each radius by means of dual-energy x-ray absorptiometry and pQCT. Each bone was subjected to a mechanical load consistent with a fall from a standing height, and measures of density and trabecular structure were compared to the compressive load. RESULTS: In the 9 bones tested, measures of bone mineral density explained approximately 50% of the variability with load (0.52 < r2 < 0.57, p < 0.03), and indices relating to the size of the marrow spaces explained an additional 25% to 30% of the variance. This held true whether the indices quantifying the marrow space were derived from the MRI images (r2 = 0.70, p = 0.03) or the pQCT images (r2 = 0.82, p = 0.006). CONCLUSION: Our findings suggest that image-based assessments of trabecular bone structure relate to bone strength in vitro.