Simultaneous 3D imaging of bone and vessel microstructure in a rat model: Measurement of vascular-trabecular interdistance

A method for simultaneous 3D imaging and analysis of microvascularization and bone microstructure in rat bone is presented. The method is based on the use of quantitative synchrotron micro-computed tomography (SR-¿CT) coupled to an automatic image analysis procedure. Previously, analysis of bone microvascularization has generally been performed from 2D histology. The proposed method enables for the first time to simultaneously analyze in 3D the microvascularization and bone microstructure in a rat model. We also propose a new parameter, utilizing the availablilty of both microstructures to relate the two, which we dub the vascular-trabecular interdistance (VTI). The proposed method was applied to investigate the effect of intermittent parathyroid hormone (PTH) administration on angiogenesis and osteogenesis in rats. It was possible to extract 3D quantitative parameters both on bone microstructure and micro-vascularization. Due to the short acquisition times of SR-¿CT and the efficiency of the image analysis algorithm, a large data set was analyzed, which permitted statistical analysis of the measured parameters. Statistical analysis showed that treatment with PTH significantly modulated several bone and vessel parameters, including the VTI.