Spatially resolved measurements of hyperpolarized gas properties in the lung in vivo. Part I: diffusion coefficient.

摘要: In imaging of hyperpolarized noble gases, a knowledge the diffusion coefficient (D) is important both as contrast mechanism and in design pulse sequences. We have made maps (3)He (129)Xe guinea pig lungs. Along length trachea, D values were on average 2.4 cm(2)/sec, closely reproducing calculated for free gas (2.05 cm(2)/sec). The measured perpendicular to trachea approximately factor two less, indicating restriction diffusion. Further evidence restricted was seen distal pulmonary airspaces 0.16 cm(2)/sec. An additional cause smaller lung due presence air, which composed heavier larger gases. results show similar trends, with averaging 0.068 cm(2)/sec 0.021 Magn Reson Med 42:721-728, 1999.