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Magnetization transfer attenuation of creatine resonances in localized proton MRS of human brain in vivo
Author(s) -
Helms Gunther,
Frahm Jens
Publication year - 1999
Publication title -
nmr in biomedicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.278
H-Index - 114
eISSN - 1099-1492
pISSN - 0952-3480
DOI - 10.1002/(sici)1099-1492(199912)12:8<490::aid-nbm593>3.0.co;2-1
Subject(s) - phosphocreatine , creatine , magnetization transfer , nuclear magnetic resonance , chemistry , metabolite , choline , attenuation , flip angle , glutamine , white matter , proton , magnetic resonance imaging , physics , endocrinology , biochemistry , medicine , optics , amino acid , radiology , energy metabolism , quantum mechanics
To assess putative magnetization transfer effects on the proton resonances of cerebral metabolites in human brain, we performed quantitative proton magnetic resonance spectroscopy (2.0 T, STEAM, TR / TE / TM = 6000/40/10 ms, LCModel data evaluation) of white matter (7.68 mL, 10 healthy young subjects) in the absence and presence of fast repetitive off‐resonance irradiation (2.1 kHz from the water resonance) using a train of 100 Gaussian‐shaped RF pulses (12.8 ms duration, 120 Hz nominal bandwidth, 40 ms repetition period, 1080° nominal flip angle). A comparison of pertinent metabolite concentrations revealed a magnetization transfer attenuation factor of the methyl and methylene resonances of creatine and phosphocreatine of 0.87 ± 0.05 ( p < 0.01). No attenuation was observed for the resonances of N ‐acetylaspartate and N ‐acetylaspartylglutamate, glutamate and glutamine, choline‐containing compounds, and myo ‐inositol. The finding for total creatine is in excellent agreement with data reported for rat brain. The results are consistent with the hypothesis of a chemical exchange of mobile creatine or phosphocreatine molecules with a small immobilized or ‘bound’ pool. Copyright © 1999 John Wiley & Sons, Ltd.