Imaging Morphometric Changes in the Human Pulmonary Acinus in Vivo Via 3He Diffusion MRI

Adam J. Hajari^1,2, James D. Quirk², Dmitriy A. Yablonskiy, ¹², Alex L. Sukstanskii², Mark S. Conradi^1,2, Jason C. Woods, ¹²

³He diffusion MRI is used to study in-vivo morphological changes at the alveolar level in human lungs. We employ a 6 b-value diffusion pulse sequence for imaging at three different levels of inspiration. An established mathematical model relating signal attenuation from the diffusion gradients to alveolar geometry is fit voxel-by-voxel to the diffusion images to determine average alveolar depth and alveolar duct radii at each of the three lung volumes. On average a 50% increase in lung volume led to a 9% increase in average alveolar duct radius and a 22% decrease in average alveolar depth.