High Resolution Spectroscopy and Chemical Shift Imaging of Hyperpolarized 129Xe Dissolved in the Human Brain In Vivo at 1.5 Tesla

Purpose: Upon inhalation, xenon diffuses into the bloodstream and is transported to the brain, where it dissolves in various compartments of the brain. Although up to five chemically distinct peaks have been previously observed in Xe-129 rat head spectra, to date only three peaks have been reported in the human head. This study demonstrates high resolution spectroscopy and chemical shift imaging (CSI) of Xe-129 dissolved in the human head at 1.5 Tesla. Methods: A Xe-129 radiofrequency coil was built in-house and Xe-129 gas was polarized using spin-exchange optical pumping. Following the inhalation of Xe-129 gas, NMR spectroscopy was performed with spectral resolution of 0.033 ppm. Two-dimensional CSI in all three anatomical planes was performed with spectral resolution of 2.1 ppm and voxel size 20mm x 20 mm. Results: Spectra of hyperpolarized Xe-129 dissolved in the human head showed five distinct peaks at 188 ppm, 192 ppm, 196 ppm, 200 ppm, and 217 ppm. Assignment of these peaks was consistent with earlier studies. Conclusion: High resolution spectroscopy and CSI of hyperpolarized Xe-129 dissolved in the human head has been demonstrated. For the first time, five distinct NMR peaks have been observed in Xe-129 spectra from the human head in vivo. (C) 2016 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine.