title: Measurement of xenon diffusing capacity in the rat lung by hyperpolarized 129Xe MRI and dynamic spectroscopy in a single breath-hold.
abstract: We used the dual capability of hyperpolarized 129Xe for spectroscopy and imaging to develop new measures of xenon diffusing capacity in the rat lung that (analogously to the diffusing capacity of carbon monoxide or DLCO) are calculated as a product of total lung volume and gas transfer rate constants divided by the pressure gradient. Under conditions of known constant pressure breath-hold, the volume is measured by hyperpolarized 129Xe MRI, and the transfer rate is measured by dynamic spectroscopy. The new quantities (xenon diffusing capacity in lung parenchyma (DLXeLP)), xenon diffusing capacity in RBCs (DLXeRBC), and total lung xenon diffusing capacity (DLXe)) were measured in six normal rats and six rats with lung inflammation induced by instillation of fungal spores of Stachybotrys chartarum. DLXeLP, DLXeRBC, and DLXe were 56 +/- 10 ml/min/mmHg, 64 +/- 35 ml/min/mmHg, and 29 +/- 9 ml/min/mmHg, respectively, for normal rats, and 27 +/- 9 ml/min/mmHg, 42 +/- 27 ml/min/mmHg, and 16 +/- 7 ml/min/mmHg, respectively, for diseased rats. Lung volumes and gas transfer times for LP (TtrLP) were 16 +/- 2 ml and 22 +/- 3 ms, respectively, for normal rats and 12 +/- 2 ml and 35 +/- 8 ms, respectively, for diseased rats. Xenon diffusing capacities may be useful for measuring changes in gas exchange associated with inflammation and other lung diseases.
authors.affiliation: Department of Physics, Carleton University, Ottawa, Ontario, Canada. nish@magma.ca
authors.forename: Nishard
authors.initials: N
authors.lastname: Abdeen
authors.forename: Albert
authors.initials: A
authors.lastname: Cross
authors.forename: Gregory
authors.initials: G
authors.lastname: Cron
authors.forename: Steven
authors.initials: S
authors.lastname: White
authors.forename: Thomas
authors.initials: T
authors.lastname: Rand
authors.forename: David
authors.initials: D
authors.lastname: Miller
authors.forename: Giles
authors.initials: G
authors.lastname: Santyr
mesh_terms: D000818:Animals; D008172:Lung Diseases, Fungal / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D011653:Pulmonary Diffusing Capacity; D051381:Rats; D017208:Rats, Wistar; D013191:Stachybotrys; D014979:Xenon Isotopes / Q000493:pharmacokinetics*
chemical_list: D014979:Xenon Isotopes