Quantitative analysis of bone trabecular structural change using X-ray bone morphometric analysis: a correlation between structural change and structural parameters

Objectives To develop an X-ray bone morphometric analysis method using a combination of morphological filter processing and bone histomorphometry.Methods Phantoms for the evaluation were prepared from a 10 × 10 × 10mm block of cancellous bone removed from a human lumbar spine and cut into five sections, each 2mm thick. Also prepared were 1.5-mm-thick phantoms of either cortical bone or soft tissue (X-ray tube side 10mm, imaging plate side 5mm). Standardized digital radiography was performed at each of five thicknesses of the cancellous bone without changing the total thickness. This was accomplished by serially replacing the 2-mm sections of the bone blocks with the soft-tissue phantoms. After morphological filter processing of the digital images, the skeletal patterns of the bone trabeculae were extracted and quantitatively assessed by bone histomorphometric analysis. The accuracy of the correlations between the trabecular structures prepared by changing the cancellous bone thickness and several structural parameters were evaluated.Results Each parameter obtained by the bone histomorphometric analysis showed a correlation coefficient ® of more than 0.89 between the cancellous bone thickness and the analytic value. Star volume analysis demonstrated a close correlation (r = 0.97) between the skeletal star volume and the bone thickness. Node-strut analysis indicated that the correlation coefficients of all of the parameters were larger than 0.93.Conclusion X-ray bone morphometric analysis that combines morphological filter processing and bone histomorphometry is clinically applicable as a computer-aided diagnosis for the evaluation of trabecular structures.