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Abstract #2542

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

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.