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(19)F spin-lattice relaxation of perfluoropolyethers: Dependence on temperature and magnetic field strength (7.0-14.1T).
- Source :
-
Journal of magnetic resonance (San Diego, Calif. : 1997) [J Magn Reson] 2014 May; Vol. 242, pp. 18-22. Date of Electronic Publication: 2014 Feb 10. - Publication Year :
- 2014
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Abstract
- Fluorine ((19)F) MRI of perfluorocarbon-labeled cells has become a powerful technique to track the migration and accumulation of cells in living organisms. It is common to label cells for (19)F MRI with nanoemulsions of perfluoropolyethers that contain a large number of chemically equivalent fluorine atoms. Understanding the mechanisms of (19)F nuclear relaxation, and in particular the spin-lattice relaxation of these molecules, is critical to improving experimental sensitivity. To date, the temperature and magnetic field strength dependence of spin-lattice relaxation rate constant (R1) for perfluoropolyethers has not been described in detail. In this study, we evaluated the R1 of linear perfluoropolyether (PFPE) and cyclic perfluoro-15-crown-5 ether (PCE) at three magnetic field strengths (7.0, 9.4, and 14.1T) and at temperatures ranging from 256-323K. Our results show that R1 of perfluoropolyethers is dominated by dipole-dipole interactions and chemical shift anisotropy. R1 increased with magnetic field strength for both PCE and PFPE. In the temperature range studied, PCE was in the fast motion regime (ωτc<1) at all field strengths, but for PFPE, R1 passed through a maximum, from which the rotational correlation time was estimated. The importance of these measurements for the rational design of new (19)F MRI agents and methods is discussed.<br /> (Copyright © 2014 Elsevier Inc. All rights reserved.)
Details
- Language :
- English
- ISSN :
- 1096-0856
- Volume :
- 242
- Database :
- MEDLINE
- Journal :
- Journal of magnetic resonance (San Diego, Calif. : 1997)
- Publication Type :
- Academic Journal
- Accession number :
- 24594752
- Full Text :
- https://doi.org/10.1016/j.jmr.2014.01.014