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Metabolite and macromolecule T 1 and T 2 relaxation times in the rat brain in vivo at 17.2T
Author(s) -
LopezKolkovsky Alfredo L.,
Mériaux Sebastien,
Boumezbeur Fawzi
Publication year - 2016
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.25602
Subject(s) - macromolecule , relaxation (psychology) , nuclear magnetic resonance , t2 relaxation , metabolite , chemistry , in vivo , spin–lattice relaxation , nuclear magnetic resonance spectroscopy , analytical chemistry (journal) , magnetic resonance imaging , chromatography , physics , biochemistry , medicine , biology , microbiology and biotechnology , nuclear quadrupole resonance , radiology
Purpose To measure the T 1 and T 2 relaxation times of water, metabolites, and macromolecules in the rat brain in vivo at 17.2T and achieve absolute quantification of the neurochemical profile. Relaxation times were compared with values from the literature found at lower magnetic fields. Methods 1 H NMR spectra were measured using a LASER localization sequence. T 1 ‐ and T 2 ‐weighted spectra were analyzed using LCModel with an original parameterization of the macromolecule baseline. Results The T 1 relaxation times of 20 metabolites and the T 2 relaxation times of 16 singlets and J‐coupled metabolites were measured. The mean T 1 and T 2 relaxation times for metabolites were 1721 ± 237 ms and 148 ± 53 ms, respectively. In addition, we measured the T 1 and T 2 relaxation times of 4 macromolecule resonance groups, their mean T 1 and T 2 relaxation times being 690 ± 100 ms and 37 ± 15 ms, respectively. Absolute quantification of 21 metabolites and 4 groups of macromolecule resonances was achieved with Cramer‐Rao Lower Bounds below 5% for Cr, Gln, Glu, GPC, Ins, NAA, PCr, and Tau and below 25% for the remaining resonances. Conclusion Comparison of our relaxation times to previously published values suggests a small increase of T 1 values and a clear decrease of T 2 values between 11.7 and 17.2T. Magn Reson Med 75:503–514, 2016. © 2015 Wiley Periodicals, Inc.