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Fast magnetization transfer and apparent T 1 imaging using a short saturation pulse with and without inversion preparation
Author(s) -
Kim Tae,
Shin Wanyong,
Kim SeongGi
Publication year - 2014
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.24756
Subject(s) - nuclear magnetic resonance , magnetization transfer , steady state (chemistry) , relaxation (psychology) , magnetic resonance imaging , saturation (graph theory) , planar , materials science , inversion (geology) , computational physics , physics , chemistry , computer science , mathematics , geology , medicine , psychology , social psychology , paleontology , combinatorics , structural basin , radiology , computer graphics (images)
Purpose Measurements of magnetization transfer (MT) metrics, such as the steady‐state (SS) MT ratio and apparent longitudinal relaxation rate require multiple MT irradiation durations and a long experimental time. To overcome these problems, we propose a novel method using a short MT off‐resonance pulse with and without on‐resonance inversion preparation pulse. Theory and Methods Computer simulations were performed to examine the accuracy of the proposed method and to find the optimal off‐resonance irradiation pulse duration ( T irad ) and power level ( ω 1 ). Our approach, with echo planar imaging data acquisition, was applied to animals at 9.4 T and humans at 3 T with ω 1 /2π = 100 Hz and 177 Hz, respectively. Steady‐state MT ratio and relaxation rate were obtained from a pair of MT images at a T irad , with and without inversion. Results For T irad ≥ 0.4 s, steady‐state MT ratio, and relaxation rate measured at any single T irad agreed well with those of the conventional fitting method that uses multiple T irad . Our simulation indicates that a higher ω 1 can use a shorter Tirad. Conclusion Steady‐state MT ratio and relaxation rate can be determined from MT data with only one, short T irad by incorporation of an inversion prepulse. This MT imaging approach is simple, fast, and easily implementable. Magn Reson Med 71:1264–1271, 2014. © 2013 Wiley Periodicals, Inc .