Estimating structural properties of trabecular bone from gray-level low-resolution images

In this paper the relationship between three-dimensional histomorphometric parameters derived from μCT and MRI images of distal radius trabecular bone samples is studied. μFE analysis of the trabecular samples is performed and Young's modulus for cranio-caudal direction is calculated. Most of the MRI and μCT parameters correlate significantly with, respectively, MRI and μCT estimates of bone volume fraction. For some of the parameters strong correlation between μCT and MRI results is also observed. However, in these cases there simultaneously exists correlation between: μCT parameter and μCT bone volume fraction; μCT and MRI bone volume fraction; MRI bone volume fraction and MRI parameter. It is found that, comparing to bone volume fraction, histomorphometric information derived from binarized MRI images does not improve estimation of the Young's modulus of trabecular bone samples (calculated for “gold standard” μCT data). Thus a novel method of “optimal paths” analysis of gray-level MRI images is introduced. “Optimal paths” parameters improve estimation of the Young's modulus of trabecular bone samples. They also provide surrogate, gray-level image-based measure of trabecular thickness.