Segmentation techniques for analysis of bone by three-dimensional computed tomographic imaging

Improved methods for evaluation and quantification of the three-dimensional (3D) architecture of bone are needed in order to more fully understand the role of trabecular architecture in bone strength. Computed tomography (microCT) is capable of examining bone at resolutions below 30 microm (isotropic), with collection of a three-dimensional data set which can then be subjected to image analysis. In this paper, we discuss automated methods for important steps in this analysis, including methods for (1) segmenting the image into bone and background; (2) defining the volume of interest for determination of structural parameters; and (3) segmenting the bone into trabecular and cortical components. Evaluation of bone structure using these techniques provides new information about the 3D architecture of bone tissue, and may be useful for evaluation of structural changes in bone caused by aging, disease, or drug treatment.