Adam J. Hajari1,2, James D. Quirk2, Dmitriy A. Yablonskiy, 12, Alex L. Sukstanskii2, Mark S. Conradi1,2, Jason C. Woods, 12
1Physics, Washington University, St. Louis, MO, United States; 2Radiology, Washington University, St. Louis, MO, United States
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.