Measurement of alveolar oxygen partial pressure in the rat lung using Carr-Purcell-Meiboom-Gill spin–spin relaxation times of hyperpolarized 3He and 129Xe at 74 mT
✍ Scribed by Ryan J. Kraayvanger; Christopher P. Bidinosti; William Dominguez-Viqueira; Juan Parra-Robles; Matthew Fox; Wilfred W. Lam; Giles E. Santyr
- Publisher
- John Wiley and Sons
- Year
- 2010
- Tongue
- English
- Weight
- 247 KB
- Volume
- 64
- Category
- Article
- ISSN
- 0740-3194
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✦ Synopsis
Abstract
Regional measurement of alveolar oxygen partial pressure can be obtained from the relaxation rates of hyperpolarized noble gases, ^3^He and ^129^Xe, in the lungs. Recently, it has been demonstrated that measurements of alveolar oxygen partial pressure can be obtained using the spin–spin relaxation rate (R~2~) of ^3^He at low magnetic field strengths (<0.1 T) in vivo. R~2~ measurements can be achieved efficiently using the Carr‐Purcell‐Meiboom‐Gill pulse sequence. In this work, alveolar oxygen partial pressure measurements based on Carr‐Purcell‐Meiboom‐Gill R~2~ values of hyperpolarized ^3^He and ^129^Xe in vitro and in vivo in the rat lung at low magnetic field strength (74 mT) are presented. In vitro spin–spin relaxivity constants for ^3^He and ^129^Xe were determined to be (5.2 ± 0.6) ×10^−6^ Pa^−1^ sec^−1^ and (7.3 ± 0.4) ×10^−6^ Pa^−1^ s^−1^ compared with spin‐lattice relaxivity constants of (4.0 ± 0.4) ×10^−6^ Pa^−1^ s^−1^ and (4.3 ± 1.3) × 10^−6^ Pa^−1^ s^−1^, respectively. In vivo experimental measurements of alveolar oxygen partial pressure using ^3^He in whole rat lung show good agreement (r^2^ = 0.973) with predictions based on lung volumes and ventilation parameters. For ^129^Xe, multicomponent relaxation was observed with one component exhibiting an increase in R~2~ with decreasing alveolar oxygen partial pressure. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.