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Using frequency‐labeled exchange transfer to separate out conventional magnetization transfer effects from exchange transfer effects when detecting ParaCEST agents
Author(s) -
Lin ChienYuan,
Yadav Nirbhay N.,
Friedman Joshua I.,
Ratnakar James,
Sherry A. Dean,
van Zijl Peter C. M.
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.24161
Subject(s) - magnetization transfer , chemistry , transfer (computing) , magnetization , nuclear magnetic resonance , physics , computer science , magnetic field , magnetic resonance imaging , medicine , radiology , quantum mechanics , parallel computing
Paramagnetic chemical exchange saturation transfer agents combine the benefits of a large chemical shift difference and a fast exchange rate for sensitive MRI detection. However, the in vivo detection of these agents is hampered by the need for high B 1 fields to allow sufficiently fast saturation before exchange occurs, thus causing interference of large magnetization transfer effects from semisolid macromolecules. A recently developed approach named frequency‐labeled exchange transfer utilizes excitation pulses instead of saturation pulses for detecting the exchanging protons. Using solutions and gel phantoms containing the europium (III) complex of DOTA tetraglycinate (EuDOTA‐(gly) − 4 ), it is shown that frequency‐labeled exchange transfer allows the separation of chemical exchange effects and magnetization transfer (MT) effects in the time domain, therefore allowing the study of the individual resonance of rapidly exchanging water molecules ( k ex >10 4 s −1 ) without interference from conventional broad‐band MT. Magn Reson Med, 2012. © 2012 Wiley Periodicals, Inc.