Magnetic resonance imaging of 1H long lived states derived from parahydrogen induced polarization in a clinical system
Magnetic resonance imaging of 1H long lived states derived from parahydrogen induced polarization in a clinical system
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DOI：
10.1016/j.jmr.2015.12.006
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发表时间：
2016-01-01
影响因子：
2.2
通讯作者：
Muennemann, Kerstin
中科院分区：
文献类型：
--
作者：
Graafen, Dirk;Belen Franzoni, Maria;Muennemann, Kerstin
超极化是克服核磁共振灵敏度低的有力工具。然而，由于弛豫过程导致的非平衡自旋态的短寿命限制了应用。这个问题可以通过将超极化存储在缓慢衰减的单重态自旋状态中来解决，到目前为止，这主要是针对非质子自旋对，例如C-13-C-13来证明的。对称分子中由仲氢诱导极化（PHIP）超极化的质子非常适合这种策略，因为它们自然地表现出长寿命的单重态。利用单重态-三重态能级的反交叉，可以实现NMR沉默单重态自旋态到可观测磁化强度的转换。在这项研究中，低功率射频脉冲序列用于此目的，它允许多个连续的单重-三重转换。在3分钟等待时间后，所产生的磁化用于在临床磁共振成像（MRI）系统中记录质子图像。我们的研究结果可能为将来使用标准MRI核H-1进行代谢成像提供前所未有的机会。(C)2016由Elsevier Inc.出版
Hyperpolarization is a powerful tool to overcome the low sensitivity of nuclear magnetic resonance (NMR). However, applications are limited due to the short lifetime of this non equilibrium spin state caused by relaxation processes. This issue can be addressed by storing hyperpolarization in slowly decaying singlet spin states which was so far mostly demonstrated for non-proton spin pairs, e.g. C-13-C-13. Protons hyperpolarized by parahydrogen induced polarization (PHIP) in symmetrical molecules, are very well suited for this strategy because they naturally exhibit a long-lived singlet state. The conversion of the NMR silent singlet spin state to observable magnetization can be achieved by making use of singlet-triplet level anticrossings. In this study, a low-power radiofrequency pulse sequence is used for this purpose, which allows multiple successive singlet-triplet conversions. The generated magnetization is used to record proton images in a clinical magnetic resonance imaging (MRI) system, after 3 min waiting time. Our results may open unprecedented opportunities to use the standard MRI nucleus H-1 for e.g. metabolic imaging in the future. (C) 2016 Published by Elsevier Inc.