<i>In vivo</i> imaging techniques for bone tissue engineering

Bone is a dynamic tissue that constantly undergoes modeling and remodeling. Bone tissue engineering relying on the development of novel implant scaffolds for the treatment of pre-clinical bone defects has been extensively evaluated by histological techniques. The study of bone remodeling, that takes place over several weeks, is limited by the requirement of a large number of animals and time-consuming and labor-intensive procedures. X-ray-based imaging methods that can non-invasively detect the newly formed bone tissue have therefore been extensively applied in pre-clinical research and in clinical practice. The use of other imaging techniques at a pre-clinical level that act as supportive tools is convenient. This review mainly focuses on nuclear imaging methods (single photon emission computed tomography and positron emission tomography), either alone or used in combination with computed tomography. It addresses their application to small animal models with bone defects, both untreated and filled with substitute materials, to boost the knowledge on bone regenerative processes.