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Inversion recovery prepared turbo spin echo sequences with reduced SAR using smooth transitions between pseudo steady states
Author(s) -
Weigel Matthias,
Zaitsev Maxim,
Hennig Juergen
Publication year - 2007
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.21170
Subject(s) - specific absorption rate , fluid attenuated inversion recovery , fast spin echo , flip angle , echo time , inversion (geology) , turbo , spin echo , nuclear magnetic resonance , pulse sequence , materials science , physics , magnetic resonance imaging , computer science , geology , telecommunications , medicine , radiology , paleontology , structural basin , automotive engineering , antenna (radio) , engineering
This study investigates the contrast behavior of 2D inversion recovery (IR) prepared turbo spin echo (TSE) sequences that use RF pulse schemes with variable low flip angles (hyperTSE) to reduce RF power deposition. A framework of equations and calculations for adapting the sequence parameters is presented by which equivalent image contrast is achieved compared to conventional IR‐TSE imaging. Although the inversion time (TI) and repetition time (TR) do not need to be changed, the echo time (TE) has to be prolonged such that the effective TE (TE eff ) is preserved. Measurements in healthy volunteers confirmed this finding for IR‐TSE sequences using different TIs: fluid attenuated inversion recovery (FLAIR), gray matter (GM)‐white matter (WM)‐IR, and short tau IR (STIR). The results demonstrate that hyperTSE sequences enable high‐quality IR‐prepared imaging with a considerably reduced specific absorption rate (SAR). Magn Reson Med 57:631–637, 2007. © 2007 Wiley‐Liss, Inc.