Surface-based anthropomorphic bone structures for use in high-resolution simulated medical imaging.

Virtual imaging trials (VITs) enable efficient assessment and optimization of medical image devices and techniques via simulation rather than physical studies. These studies require an accurate simulation model of the imaging system and realistic, detailed ground-truth models or phantoms of the relevant anatomy or physiology. Anatomical structures within computational phantoms are typically based on medical imaging data, usually CT or MRI. However, for small and intricate structures (e.g., trabecular bone), it is not reasonable to use existing clinical data to inform a computational model, as the spatial resolution of the scans is insufficient. This resolution results in fine trabecular structures presenting as an image feature or texture rather than morphology. Previously, we developed a method to model the appearance of CT-imaged trabecular bone with synthetic textures based on imaging data. In this study, we develop a mathematical method to generate arbitrary-resolution bone structures within virtual patient models (XCAT phantoms). The method was used to generate trabecular and cortical structures of 46 chest bones as discrete, watertight, 2-manifold (polygon meshes) having regions of bone and red marrow. The produced models were validated in comparison with published properties of bones. The utility of the method was demonstrated with pilot CT and photon-counting CT simulations performed using the accurate DukeSim CT simulator on XCAT computational phantoms containing the detailed bone models. The results show the great potential the developed tools have to provide ground truth simulations to access the ability of CT imaging technology to provide quantitative information about bone structures.