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Combining CW and pulsed saturation allows in vivo quantitation of magnetization transfer observed for total creatine by 1 H‐NMR‐spectroscopy of rat brain
Author(s) -
Roell Stefan A.,
Dreher Wolfgang,
Leibfritz Dieter
Publication year - 1999
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/(sici)1522-2594(199908)42:2<222::aid-mrm2>3.0.co;2-d
Subject(s) - magnetization transfer , nuclear magnetic resonance , nuclear magnetic resonance spectroscopy , creatine , in vivo , saturation (graph theory) , spectroscopy , chemistry , analytical chemistry (journal) , magnetic resonance imaging , biology , medicine , physics , biochemistry , chromatography , radiology , microbiology and biotechnology , mathematics , combinatorics , quantum mechanics
Selective saturation of bound nuclei attenuates the MR visible CH 2 and the CH 3 signal of total creatine (tCr) in rat brain in vivo. The low contrast to noise ratio achieved during the limited experiment time makes it difficult to quantify the effect. It is shown that by combining data from continuous‐wave and pulsed saturation experiments, quantitation is possible using the standard magnetization transfer model. The model parameters obtained are the transverse relaxation time of the bound spin fraction B, T 2 R = 31 ± 8 μs, the exchange rate r x = 0.36 ± 0.04 s −1 , and the concentration ratio of bound nuclei taking part in the exchange to free tCr magnetization, f = M 0 B / M 0 A = 0.04 ± 0.01. The phenomenon can be explained by either an intermolecular exchange of free and bound creatine molecules or by through‐space interaction with bound nuclei showing not necessarily the same chemical shift. Magn Reson Med 42:222–227, 1999. © 1999 Wiley‐Liss, Inc.