MicroCT-based imaging of microvasculature within the bone tissue

Angiogenesis is a physiological process essential for skeletal development and growth, for bone healing and regeneration. Various research areas, including implantology and tissue engineering, would benefit from improved three-dimensional (3D) imaging of the vasculature within bone tissue. In the last decades, X-ray microtomography (microCT) has gained recognition as a non-destructive 3D imaging technique for bone morphology. The structural nature of skeletal tissue has rendered the direct 3D imaging of its vasculature extremely difficult. For the detection of the vessels, contrast or casting agents must be used. A major drawback of such an approach has been the limited contrast between the common perfusion agents and mineralized tissue, which makes their distinct segmentation problematic. The usually applied decalcification resolves this issue but makes simultaneous assessment of the intracortical bone microstructure and the vascular morphology impossible. Moreover, the problem of contrasting becomes compounded in the presence of a metal implant. Herewith we introduce the micro Angiofil-enhanced microCT-based visualization of vasculature within bone tissue in various small and large animal models, with and without decalcification. This study documents simultaneous microvascular and bone imaging in murine tibia, murine bone metastatic model, pulp chamber, gingiva and periodontal ligaments. In a large animal model (minipig) we present the visualization and segmentation of different tissue types and vessels in the hemimandible containing several metal implants. Herewith we provide for the first time a non-destructive 3D imaging approach of the vasculature within soft and hard tissues in the vicinity of metal implants in a large animal model. ### Competing Interest Statement The authors have declared no competing interest.