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Influence of the FID and off‐resonance effects in dense MRI
Author(s) -
Haraldsson Henrik,
Sigfridsson Andreas,
Sakuma Hajime,
Engvall Jan,
Ebbers Tino
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.22692
Subject(s) - displacement (psychology) , nuclear magnetic resonance , free induction decay , residual , in vivo , magnetic resonance imaging , relaxation (psychology) , resonance (particle physics) , signal (programming language) , chemistry , materials science , spin echo , physics , computer science , medicine , algorithm , atomic physics , biology , radiology , psychology , microbiology and biotechnology , programming language , psychotherapist
Accurate functional measurement in cardiovascular diseases is important as inaccuracy may compromise diagnostic decisions. Cardiac function can be assessed using displacement encoding with stimulated echoes, resulting in three signal components. The free induction decay (FID), arising from spins undergoing T 1 ‐relaxation, is not displacement encoded and impairs the displacement acquired. Techniques for suppressing the FID exist; however, a residual will remain. The effect of the residual is difficult to distinguish and investigate in vitro and in vivo. In this work, the influence of the FID as well as of off‐resonance effects is evaluated by altering the phase of the FID in relation to the stimulated echo. The results show that the FID and off‐resonance effects can impair the accuracy of the displacement measurement acquired. The influence of the FID can be avoided by using an encoded reference. We therefore recommend the assessment of this influence of the FID for each displacement encoding with stimulated echoes protocol. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.