Distribution and dynamics of laser‐polarized 129Xe magnetization in vivo

Abstract

The first magnetic resonance imaging studies of laser-polarized 129 Xe, dissolved in the blood and tissue of the lungs and the heart of Sprague-Dawley rats, are described. 129 Xe resonances at 0, 192, 199, and 210 ppm were observed and assigned to xenon in gas, fat, tissue, and blood, respectively. One-dimensional chemical-shift imaging (CSI) reveals xenon magnetization in the brain, kidney, and lungs. Coronal and axial twodimensional CSI show 129 Xe dissolved in blood and tissue in the thorax. Images of the blood resonance show xenon in the lungs and the heart ventricle. Images of the tissue resonance reveal xenon in lung parenchyma and myocardium. The 129 Xe spectrum from a voxel located in the heart ventricle shows a single blood resonance. Time-resolved spectroscopy shows that the dynamics of the blood resonance match the dynamics of the gas resonance and demonstrates efficient diffusion of xenon gas to the lung parenchyma and then to pulmonary blood. These observations demonstrate the utility of laser-polarized 129

Simultaneous magnetic resonance imaging of ventilation distribution and gas uptake in the human lung using hyperpolarized xenon-129

“…Clearly, hyperpolarized Xe129, transported through the vasculature, was concentrated in the region of the nodule over the course of the breath-hold acquisition. The signal contribution from Xe129 in the blood that has traveled to a location distant from the airspaces, such as to a solid lesion or the major vessels and heart, should depend on the frequency and amplitude of radiofrequency excitation (6,9,10). Thus, by selecting appropriate acquisition parameters, it should be possible to highlight Xe129 that has just dissolved in tissue versus Xe129 that has been transported away from the airspaces.…”

Nuclear magnetic resonance of laser-polarized noble gases in molecules, materials and organisms

“…Two 12gXeCSIS It is interesting to note that in this study, only one resonance was observed that could be assigned to blood in the 129XeIWIR. spectra (with a chemical shift of w21O ppm, obtained, for example, from localized NMR spectroscopy from the rat's heart region) [233]. This result suggests that under the conditions of their experiment (e.g., xenon dissolved in rat blood in vivo at 37 "C and 2 T) the xenon exchange between RBCS and plasma was contrast to the previous in vitro fast with respect to the the NMR time scale, in results involving xenon in human blood at higher fields and ambient conditions [224,225].…”

Nuclear Magnetic Resonance of Laser-Polarized Noble Gases in Molecules, Materials, and Organisms

“…following respiration of laser-polarized xenon by laboratory rats [233]. Two 12gXeCSIS It is interesting to note that in this study, only one resonance was observed that could be assigned to blood in the 129XeIWIR.…”