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Abstract #2177

Alveolar-Duct Geometry During Expiration Via 3He Diffusion MRI

Adam Hajari1, Dmitriy Yablonskiy1,2, James Quirk2, Alex Sukstanskii2, Mark Conradi1,2, Richard Pierce3, Gaetan Deslee3, Jason Woods1,2

1Physics, Washington University, St. Louis, MO, USA; 2Radiology, Washington University, St. Louis, MO, USA; 3Internal Medicine, Washington University, St. Louis, MO, USA

Acinar geometry has been the subject of several morphological and imaging studies in the past; however, little is known about how acinar microstructure changes when the lung inflates or deflates. Lung morphometry with hyperpolarized 3He diffusion MRI allows evaluation of lung microstructural geometrical parameters. We have determined these parameters during the inflation cycle at physiologically relevant volumes by ex-vivo 3He diffusion MRI in five healthy canine lungs. Our results imply that during a change in lung volume from TLC to 60% of TLC, the outer acinar airway radius changes by 16% while the alveolar wall length remains near constant.