In vivo 129Xe NMR in rat brain during intra-arterial injection of hyperpolarized 129Xe dissolved in a lipid emulsion

129Xe spectra from the heads of rats with and without ligation of the external carotid and pterygopalatine arteries

“…Indeed, ␣-chloralose is often used in functional activation studies because it is empirically found to interfere less with neuronal response. In previous studies of hyperpolarized 129 Xe rat head spectra, anesthesia was maintained with halothane (3,(11)(12)(13)(14), chloral hydrate (7-9), or a ketamine/xylazine mixture (16,17). As noted above, only the spectrum published by Rosen et al (13,14) contained peaks corresponding to peaks D and E observed in the present study.…”

“…Previous in vivo investigations of hyperpolarized xenon in the rat head have failed to produce consistent spectra (3,4,(7)(8)(9)(11)(12)(13)(14)(15)(16)(17). One group obtained spectra with a single dominant peak positioned within the chemical shift range of 194 -199 ppm relative to the gas phase peak (3,4,12).…”

“…In that study, it was suggested that the sources of the two peaks were xenon-dissolved in comparatively lipid-rich and lipid-poor brain tissue. Adding further to the confusion are the spectra obtained after intracarotid injection of xenon dissolved in a lipid emulsion (7)(8)(9)11). The spectra contained two peaks at 194.5 ppm and 199 ppm that were assigned to xenon in the emulsion and brain tissue, respectively.…”

Cerebral perfusion assessment by bolus tracking using hyperpolarized 13C

“…However, a potential problem is the influence of tracer depolarization, a result of the nonequilibrium nuclear spin population, on the derived parameters. Perfusion studies using hyperpolarized tracers have been performed earlier using 129 Xe for cerebral applications (16,17), and 3 He encapsulated in microbubbles has been used for studies of various tissues (18,19). For both of these isotopes the potential signal enhancement due to high polarization was of limited benefit due to the low concentration of the tracer.…”

Development of a Hyperpolarized 129Xe System on 3T for the Rat Lungs

“…[2][3][4][5] On the other hand, the advantage of 129 Xe is its a‹nity for lipids and lack of a need for isotopic condensation, which limits clinical use. Hyperpolarized 129 Xe (HPXe) has a long T1 even in blood (up to 10 s) [6][7][8][9][10] and can be delivered to any organ by simple inhalation [11][12][13][14][15][16][17] or by invasive injection [18][19][20][21] to provide a high signal. HPXe diŠuses freely and passes through the bloodbrain barrier, unlike the conventional gadolinium chelate compound 22 ; therefore, it is expected to be adopted as a new exogenous NMR (nuclear magnetic resonance) tracer for cerebral perfu- Polarizer incorporating an optical pumping technique with batch transfer.…”