Quantitative in vivo assessment of lung microstructure at the alveolar level with hyperpolarized super(3)He diffusion MRI

• Published in: Proceedings of the National Academy of Sciences - PNAS 2002-03, Vol.99 (5), p.3111-3116
• Main Authors: Yablonskiy, DA, Sukstanskii, AL, Leawoods, J C, Gierada, D S, Bretthorst, G L, Lefrak, S S, Cooper, J D, Conradi, MS
• Format: Article
• Language: English
• Subjects: helium
• ISSN: 0027-8424
• DOI: 10.1073/pnas.052594699

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 super(3)He diffusion MRI in healthy human subjects and patients with severe emphysema. We also provide the first experimental data demonstrating that super(3)He 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.