Probing the regional distribution of pulmonary gas exchange through single-breath gas- and dissolved-phase 129Xe MR imaging
| Autor: | Bastiaan Driehuys, H. Page McAdams, S. Sivaram Kaushik, Zackary I. Cleveland, Kevin T. Kelly, Scott H. Robertson, W. Michael Foster, Matthew S. Freeman, Mu He, Rohan S. Virgincar, John Davies, Jane V. Stiles |
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| Rok vydání: | 2013 |
| Předmět: |
Adult
Male Physiology Analytical chemistry Ventilation/perfusion ratio Pulmonary function testing Young Adult Imaging Three-Dimensional Nuclear magnetic resonance Physiology (medical) Prone Position Supine Position Isotopes of xenon medicine Humans Distribution (pharmacology) Lung Aged Pulmonary Gas Exchange Chemistry Articles Single breath Middle Aged Magnetic Resonance Imaging Mr imaging Healthy Volunteers medicine.anatomical_structure Dissolved phase Xenon Isotopes Female |
| Zdroj: | Journal of Applied Physiology. 115:850-860 |
| ISSN: | 1522-1601 8750-7587 |
| Popis: | Although some central aspects of pulmonary function (ventilation and perfusion) are known to be heterogeneous, the distribution of diffusive gas exchange remains poorly characterized. A solution is offered by hyperpolarized 129Xe magnetic resonance (MR) imaging, because this gas can be separately detected in the lung's air spaces and dissolved in its tissues. Early dissolved-phase 129Xe images exhibited intensity gradients that favored the dependent lung. To quantitatively corroborate this finding, we developed an interleaved, three-dimensional radial sequence to image the gaseous and dissolved 129Xe distributions in the same breath. These images were normalized and divided to calculate “129Xe gas-transfer” maps. We hypothesized that, for healthy volunteers, 129Xe gas-transfer maps would retain the previously observed posture-dependent gradients. This was tested in nine subjects: when the subjects were supine, 129Xe gas transfer exhibited a posterior-anterior gradient of −2.00 ± 0.74%/cm; when the subjects were prone, the gradient reversed to 1.94 ± 1.14%/cm ( P < 0.001). The 129Xe gas-transfer maps also exhibited significant heterogeneity, as measured by the coefficient of variation, that correlated with subject total lung capacity ( r = 0.77, P = 0.015). Gas-transfer intensity varied nonmonotonically with slice position and increased in slices proximal to the main pulmonary arteries. Despite substantial heterogeneity, the mean gas transfer for all subjects was 1.00 ± 0.01 while supine and 1.01 ± 0.01 while prone ( P = 0.25), indicating good “matching” between gas- and dissolved-phase distributions. This study demonstrates that single-breath gas- and dissolved-phase 129Xe MR imaging yields 129Xe gas-transfer maps that are sensitive to altered gas exchange caused by differences in lung inflation and posture. |
| Databáze: | OpenAIRE |
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