title: Oxygen-dependent hyperpolarized (129) Xe brain MR.
abstract: Hyperpolarized (HP) (129) Xe MR offers unique advantages for brain functional imaging (fMRI) because of its extremely high sensitivity to different chemical environments and the total absence of background noise in biological tissues. However, its advancement and applications are currently plagued by issues of signal strength. Generally, xenon atoms found in the brain after inhalation are transferred from the lung via the bloodstream. The longitudinal relaxation time (T1 ) of HP (129) Xe is inversely proportional to the pulmonary oxygen concentration in the lung because oxygen molecules are paramagnetic. However, the T1 of (129) Xe is proportional to the pulmonary oxygen concentration in the blood, because the higher pulmonary oxygen concentration will result in a higher concentration of diamagnetic oxyhemoglobin. Accordingly, there should be an optimal pulmonary oxygen concentration for a given quantity of HP (129) Xe in the brain. In this study, the relationship between pulmonary oxygen concentration and HP (129) Xe signal in the brain was analyzed using a theoretical model and measured through in vivo experiments. The results from the theoretical model and experiments in rats are found to be in good agreement with each other. The optimal pulmonary oxygen concentration predicted by the theoretical model was 21%, and the in vivo experiments confirmed the presence of such an optimal ratio by reporting measurements between 25% and 35%. These findings are helpful for improving the (129) Xe signal in the brain and make the most of the limited spin polarization available for brain experiments. Copyright © 2016 John Wiley & Sons, Ltd.
authors.affiliation: Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, 430071, China.
authors.forename: Haidong
authors.initials: H
authors.lastname: Li
authors.affiliation: Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, 430071, China.
authors.forename: Zhiying
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, 430071, China.
authors.forename: Jianping
authors.initials: J
authors.lastname: Zhong
authors.affiliation: Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, 430071, China.
authors.forename: Weiwei
authors.initials: W
authors.lastname: Ruan
authors.affiliation: Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, 430071, China.
authors.forename: Yeqing
authors.initials: Y
authors.lastname: Han
authors.affiliation: Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, 430071, China.
authors.forename: Xianping
authors.initials: X
authors.lastname: Sun
authors.affiliation: Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, 430071, China.
authors.forename: Chaohui
authors.initials: C
authors.lastname: Ye
authors.affiliation: Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, 430071, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Zhou
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism*; D003198:Computer Simulation; D008168:Lung / Q000378:metabolism; D008279:Magnetic Resonance Imaging; D010100:Oxygen / Q000378:metabolism*; D017207:Rats, Sprague-Dawley; D014978:Xenon / Q000378:metabolism*; D014979:Xenon Isotopes
chemical_list: D014979:Xenon Isotopes; D014978:Xenon; D010100:Oxygen
keywords: SEOP; brain MRI; hyperpolarized 129Xe; oxygen concentration