title: Quantitative in vivo assessment of lung microstructure at the alveolar level with hyperpolarized 3He diffusion MRI.
abstract: The study of lung emphysema dates back to the beginning of the 17th century. Nevertheless, a number of important questions remain unanswered because a quantitative localized characterization of emphysema requires knowledge of lung structure at the alveolar level in the intact living lung. This information is not available from traditional imaging modalities and pulmonary function tests. Herein, we report the first in vivo measurements of lung geometrical parameters at the alveolar level obtained with 3He diffusion MRI in healthy human subjects and patients with severe emphysema. We also provide the first experimental data demonstrating that 3He gas diffusivity in the acinus of human lung is highly anisotropic. A theory of anisotropic diffusion is presented. Our results clearly demonstrate substantial differences between healthy and emphysematous lung at the acinar level and may provide new insights into emphysema progression. The technique offers promise as a clinical tool for early diagnosis of emphysema.
authors.affiliation: Department of Radiology, Washington University School of Medicine, 4525 Scott Avenue, St. Louis, MO 63110, USA. yablonskiy@mir.wustl.edu
authors.forename: Dmitriy A
authors.initials: DA
authors.lastname: Yablonskiy
authors.forename: Alexander L
authors.initials: AL
authors.lastname: Sukstanskii
authors.forename: Jason C
authors.initials: JC
authors.lastname: Leawoods
authors.forename: David S
authors.initials: DS
authors.lastname: Gierada
authors.forename: G Larry
authors.initials: GL
authors.lastname: Bretthorst
authors.forename: Stephen S
authors.initials: SS
authors.lastname: Lefrak
authors.forename: Joel D
authors.initials: JD
authors.lastname: Cooper
authors.forename: Mark S
authors.initials: MS
authors.lastname: Conradi
mesh_terms: D004058:Diffusion; D004646:Emphysema / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000503:physiopathology; D006371:Helium; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging* / Q000503:physiopathology; D008279:Magnetic Resonance Imaging / Q000379:methods; D008953:Models, Anatomic; D011859:Radiography
chemical_list: D006371:Helium