Publications [#132869] of G. Allan Johnson
- XJ Chen, HE Möller, MS Chawla, GP Cofer, B Driehuys, LW Hedlund, GA Johnson, Spatially resolved measurements of hyperpolarized gas properties in the lung in vivo. Part I: diffusion coefficient.,
Magnetic resonance in medicine : official journal of the Society of Magnetic Resonance in Medicine / Society of Magnetic Resonance in Medicine, UNITED STATES, vol. 42 no. 4
pp. 721-8, ISSN 0740-3194
(last updated on 2005/08/03)
In imaging of hyperpolarized noble gases, a knowledge of the diffusion coefficient (D) is important both as a contrast mechanism and in the design of pulse sequences. We have made diffusion coefficient maps of both hyperpolarized (3)He and (129)Xe in guinea pig lungs. Along the length of the trachea, (3)He D values were on average 2.4 cm(2)/sec, closely reproducing calculated values for free gas (2.05 cm(2)/sec). The (3)He D values measured perpendicular to the length of the trachea were approximately a factor of two less, indicating restriction to diffusion. Further evidence of restricted diffusion was seen in the distal pulmonary airspaces as the average (3)He D was 0.16 cm(2)/sec. An additional cause for the smaller (3)He D in the lung was due to the presence of air, which is composed of heavier and larger gases. The (129)Xe results show similar trends, with the trachea D averaging 0.068 cm(2)/sec and the lung D averaging 0.021 cm(2)/sec. Magn Reson Med 42:721-728, 1999.
Animals • Guinea Pigs • Helium • Isotopes • Lung • Magnetic Resonance Imaging • Pulmonary Diffusing Capacity • Xenon Isotopes • anatomy & histology* • diagnostic use • methods*