A method for evaluating the murine pulmonary vasculature using micro-computed tomography

Abstract Introduction Significant mortality and morbidity is associated with alterations in the pulmonary vasculature. While techniques have been described for quantitative morphometry of whole-lung arterial trees in larger animals, no methods have been described in mice. We report a method for the quantitative assessment of murine pulmonary arterial vasculature using high resolution CT scanning. Methods Mice were harvested at 2-weeks, 4-weeks, and 3-months of age. The pulmonary artery vascular tree was pressure perfused to maximal dilation with a radio-opaque casting material with viscosity and pressure set to prevent capillary transit and venous filling. The lungs were fixed and scanned on a specimen CT scanner at 8um resolution and the vessels segmented. Vessels were grouped into categories based upon lumen diameter and branch generation. Results Robust high-resolution segmentation was achieved, permitting detailed quantitation of pulmonary vascular morphometrics. As expected, postnatal lung development was associated with progressive increase in small-vessel number and arterial branching complexity. Conclusion These methods for quantitative analysis of the pulmonary vasculature in postnatal and adult mice provide a useful tool for the evaluation of mouse models of disease that affect the pulmonary vasculature.