title: Method to determine in vivo the relaxation time T1 of hyperpolarized xenon in rat brain.
abstract: The magnetic polarization of the stable (129)Xe isotope may be enhanced dramatically by means of optical techniques and, in principle, hyperpolarized (129)Xe MRI should allow quantitative mapping of cerebral blood flow with better spatial resolution than scintigraphic techniques. A parameter necessary for this quantitation, and not previously known, is the longitudinal relaxation time (T(1) (tissue)) of (129)Xe in brain tissue in vivo: a method for determining this is reported. The time course of the MR signal in the brain during arterial injection of hyperpolarized (129)Xe in a lipid emulsion was analyzed using an extended two-compartment model. The model uses experimentally determined values of the RF flip angle and the T(1) of (129)Xe in the lipid emulsion. Measurements on rats, in vivo, at 2.35 T gave T(1) (tissue) = 3.6 +/- 2.1 sec (+/-SD, n = 6). This method enables quantitative mapping of cerebral blood flow.
authors.affiliation: Laboratoire de Biomécanique, Université Louis Pasteur, Centre Hospitalier Universitaire Hautepierre, Strasbourg, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Choquet
authors.forename: Jean-Noël
authors.initials: JN
authors.lastname: Hyacinthe
authors.forename: Guillaume
authors.initials: G
authors.lastname: Duhamel
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Grillon
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Leviel
authors.forename: André
authors.initials: A
authors.lastname: Constantinesco
authors.forename: Anne
authors.initials: A
authors.lastname: Ziegler
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism*; D002560:Cerebrovascular Circulation; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008959:Models, Neurological; D051381:Rats; D017207:Rats, Sprague-Dawley; D014979:Xenon Isotopes / Q000378:metabolism*
chemical_list: D014979:Xenon Isotopes