Quantification of the pulmonary vasculature in mice under chronic hypoxia with contrast-free pulmonary angiography in vivo imaging.

Innovative advancements in preclinical imaging have led to the development of cone-beam computed tomography (CBCT) combined with contrast-free pulmonary angiography (CFPA), a novel lung scanning technology capable of assessing lung function and pulmonary vascular morphology. This cutting-edge approach integrates CBCT to provide detailed quantification of the pulmonary vascular tree. The application of this technique to image and quantify changes in the pulmonary vascular tree of mice exposed to chronic hypoxia has not been investigated. In this study, we investigated the feasibility of utilizing CFPA for imaging changes in the murine lung vascular bed under chronic hypoxia and assessed whether vascular metrics correlate with hematologic parameters and/or right ventricular pressure and mass. Our results revealed a significant increase in hemoglobin and total pulmonary vascular blood volume, as well as total pulmonary vessel length following exposure to chronic hypoxia. The pulmonary vascular blood volume and total vessel length strongly correlated with hemoglobin. There was also an increase in pulmonary arterial pressure and right ventricular mass under hypoxia that was linked to the hematological response and the changes in the pulmonary vascular bed. These findings highlight the application of preclinical CBCT and CFPA imaging as a valuable tool for visual and quantitative analysis of the pulmonary vasculature in preclinical models of chronic hypoxia and its potential use in investigating other pulmonary vasculopathies.