Imaging lung microstructure in mice with hyperpolarized ³He diffusion MRI

Quantitative measurement of lung microstructure is of great significance in assessment of pulmonary disease, particularly in the earliest stages. The technique for MRI-based ³He lung morphometry was previously developed and validated for human lungs, and was recently extended to ex vivo mouse lungs. The technique yields accurate, quantitative information about the microstructure and geometry of acinar airways. In this study, the ³He lung morphometry technique is successfully implemented for in vivo studies of mice. Results indicate excellent agreement between in vivo morphometry via ³He MRI and microscopic morphometry after sacrifice. This opens up new avenues for application of the technique as a precise, noninvasive, in vivo biomarker of changes in lung microstructure, within various mouse models of lung disease.