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Understanding quantitative pulsed CEST in the presence of MT
Author(s) -
Desmond Kimberly L.,
Stanisz Greg J.
Publication year - 2012
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.23074
Subject(s) - magnetization transfer , magnetization , chemistry , imaging phantom , nuclear magnetic resonance , bloch equations , ammonium chloride , saturation (graph theory) , analytical chemistry (journal) , magnetic field , physics , optics , chromatography , magnetic resonance imaging , mathematics , medicine , quantum mechanics , combinatorics , radiology
Phantom experiments in agar and ammonium chloride were performed to evaluate a three‐pool model of magnetization transfer and chemical exchange saturation transfer (CEST) in a pulsed saturation transfer experiment. The utility of the pulsed CEST method was demonstrated by varying the pH of the phantoms and observing the effect upon the CEST spectra both with and without the solid agar (the magnetization transfer pool), while fitting the spectra to the Bloch equation model with exchange. Pulsed CEST could be used to robustly quantify parameters related to CEST, including the exchange rate constant describing proton exchange with free water and the concentration of exchanging protons. Furthermore, the exchange rate constant and the CEST pool offset frequency of the ammonium chloride remained unchanged in the presence of a magnetization transfer pool. The logarithm of the fitted exchange rate constant was linearly related to pH: this relationship was maintained in the presence of magnetization transfer. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.