A new bone vascular perfusion compound for the simultaneous analysis of bone and vasculature

Bone is a highly vascular tissue, which plays an important role in bone development and healing. The ability to analyze both the bone and vasculature simultaneously can enhance the understanding of wound healing, development, and disease in bone. At present, analysis methods are limited in their ability to allow for this simultaneous analysis of bone and bone vasculature in three dimensions, without using the most recent dual-energy computed tomography (CT) techniques. In this study, we present a new barium sulfate (BaSO(4)) radiopaque vascular perfusion compound for performing postmortem microangiography with single-beam microcomputed tomography (microCT), which allows for such simultaneous analysis. This compound differs from currently available contrast mediums due to (1) the high weight-to-volume ratio of BaSO(4) achieved, (2) small BaSO(4) aggregate size (<5 microm), (3) minimal additives, and (4) its miscibility with blood and saline. Most notably, it achieves a radiodensity of 2.4x that of cortical bone, with high perfusion of both the arterial and venous systems and the intervening capillary bed, resulting in an in vivo radiodensity that ranges from that of bone to titanium. Our results, verified using a rat femoral gap-healing model, show that the compound is uniquely suited to high-contrast imaging of the vasculature in the presence of undecalcified bone, with a versatility to be used in other tissues.