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Finite RF pulse correction on DESPOT2
Author(s) -
Crooijmans H. J. A.,
Scheffler K.,
Bieri O.
Publication year - 2011
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.22661
Subject(s) - precession , pulse (music) , magnetization , steady state (chemistry) , relaxation (psychology) , magnetization transfer , nuclear magnetic resonance , excitation , radio frequency , pulse duration , physics , materials science , computational physics , atomic physics , optics , chemistry , magnetic field , condensed matter physics , magnetic resonance imaging , laser , computer science , quantum mechanics , medicine , telecommunications , detector , radiology
Magnetization transfer and finite radiofrequency (RF) pulses affect the steady state of balanced steady state free precession. As quantification of transverse relaxation ( T 2 ) with driven equilibrium single pulse observation of T 2 is based on two balanced steady state free precession acquisitions, both effects can influence the outcome of this method: a short RF pulse per repetition time ( T RF /TR ≪ 1) leads to considerable magnetization transfer effects, whereas prolonged RF pulses ( T RF /TR > 0.2) minimize magnetization transfer effects, but lead to increased finite pulse effects. A correction for finite pulse effects is thus implemented in the driven equilibrium single pulse observation of T 2 theory to compensate for reduced transverse relaxation effects during excitation. It is shown that the correction successfully removes the driven equilibrium single pulse observation of T 2 dependency on the RF pulse duration. A reduction of the variation in obtained T 2 from over 50% to less than 10% is achieved. We hereby provide a means of acquiring magnetization transfer‐free balanced steady state free precession images to yield accurate T 2 values using elongated RF pulses. Magn Reson Med, 2011. © 2010 Wiley‐Liss, Inc.