期刊
JOURNAL OF MAGNETIC RESONANCE
卷 276, 期 -, 页码 78-85出版社
ACADEMIC PRESS INC ELSEVIER SCIENCE
DOI: 10.1016/j.jmr.2017.01.014
关键词
NMR; MRI; Low field; Hyperpolarization; Parahydrogen; Long-lived spin states; Propane
资金
- NIH [1R21EB018014, 1R21EB020323, 1F32EB021840]
- NSF [CHE1416268, CHE-1416432]
- DOD CDMRP [W81XWH-12-1-0159/ BC112431, W81XVVH-15-1-0271, W81XVVH-15-1-0272]
- Russian Foundation for Basic Research (RFBR) [16-03-00407]
- Direct For Mathematical & Physical Scien
- Division Of Chemistry [1416432] Funding Source: National Science Foundation
- Division Of Chemistry
- Direct For Mathematical & Physical Scien [1416268] Funding Source: National Science Foundation
When parahydrogen reacts with propylene in low magnetic fields (e.g., 0.05 T), the reaction product propane develops an overpopulation of pseudo-singlet nuclear spin states. We studied how the Spin-Lock Induced Crossing (SLIC) technique can be used to convert these pseudo-singlet spin states of hyperpolarized gaseous propane into observable magnetization and to detect H-1 NMR signal directly at 0.05 T. The theoretical simulation and experimental study of the NMR signal dependence on B-1 power (SLIC amplitude) exhibits a well-resolved dispersion, which is induced by the spin-spin couplings in the eight-proton spin system of propane. We also measured the exponential decay time constants (T-uss or T-s) of these pseudo-singlet long-lived spin states (LISS) by varying the time between hyperpolarized propane production and SLIC detection. We have found that, on average, Ts is approximately 3 times longer than the corresponding T-1 value under the same conditions in the range of pressures studied (up to 7.6 atm). Moreover, T-s may exceed 13 s at pressures above 7 atm in the gas phase. These results are in agreement with the previous reports, and they corroborate a great potential of long-lived hyperpolarized propane as an inhalable gaseous contrast agent for lung imaging and as a molecular tracer to study porous media using low-field NMR and MRI. (C) 2017 Elsevier Inc. All rights reserved.
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