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.