Photoacoustic imaging for the study of oxygen saturation and total hemoglobin in bone healing and non-union formation
Maximilian M. Menger, Christina Körbel, David Bauer, Michelle Bleimehl, Anne L. Tobias, Benedikt J. Braun, Steven C. Herath, Mika F. Rollmann, Matthias W. Laschke, Michael D. Menger, Tina Histing
Abstract
Non-union formation represents a major complication in trauma surgery. Adequate vascularization has been recognized as vital for bone healing. However, the role of vascularization in the pathophysiology of non-union formation remains elusive. This is due to difficulties in studying bone microcirculation in vivo. Therefore, we herein studied in a murine osteotomy model whether photoacoustic imaging may be used to analyze vascularization in bone healing and non-union formation. We found that oxygen saturation within the callus tissue is significantly lower in non-unions compared to unions and further declines over time. Moreover, the amount of total hemoglobin (HbT) within the callus tissue was markedly reduced in non-unions. Correlation analyses showed a strong positive correlation between microvessel density and HbT, indicating that photoacoustically determined HbT is a valid parameter to assess vascularization during bone healing. In summary, photoacoustic imaging is a promising approach to study vascular function and tissue oxygenation in bone regeneration.