Microcomputational analysis of the resultant heterotopic bone formation. (A, D) Three-dimensional surface renderings of the resultant heterotopic bone. (B, E) Cross-sectional slices through the new bone. (C, F) Corresponding radiograms. (A–F) The resultant mineralization of the muscle tissues after injection of AdBMP2-transduced cells (2500 VP/cell) encapsulated into PEGDA microspheres (A–C) or direct injection of unencapsulated AdBMP2-transduced cells (D–F). Both have a denser rim of bone, with a hollow interior structure, suggesting that the biomaterial did not alter bone patterning.