Tissue engineering applications of microcomputed tomography (micro-CT) imaging

High resolution x-ray microcomputed tomography (micro-CT) was first developed in the early 1980's and has since been applied widely in material science and bioengineering research. Micro-CT combines x-ray projections from multiple viewing directions to nondestructively provide 3D reconstructed images of samples at voxel resolutions of 6-50 microns. The micro-CT system at Georgia Tech is capable of imaging ceramics, polymers, and mineralized tissues up to 38 mm in diameter and 80 mm in length. After the reconstructed images are thresholded, stereological algorithms are used to quantify parameters related to the amount and microstructural organization of the material within the samples. Since the imaging process is nondestructive, the internal features of the same sample may be examined multiple times over time and samples remain available for additional biological and mechanical evaluation. Recent applications of micro-CT to characterize structure-function relationships in trabecular bone and porous biomaterial scaffolds will be described. In addition, the ability to quantify alterations in bone microstructure resulting from therapeutic treatments, mechanical stimulation, or genetic engineering will be described. Finally, the use of micro-CT as a quantitative outcome measure for bone tissue engineering studies will be introduced.