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Motion‐sensitized driven equilibrium for blood‐suppressed T2* mapping
Author(s) -
Newbould Rexford D.,
Owen David R.J.,
Shalhoub Joseph,
Brown Andrew P.,
Gambarota Giulio
Publication year - 2011
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.22664
Subject(s) - flip angle , nuclear magnetic resonance , gradient echo , signal (programming language) , intensity (physics) , carotid arteries , medicine , nuclear medicine , biomedical engineering , magnetic resonance imaging , radiology , physics , computer science , optics , programming language
Purpose: To combine a motion‐sensitized driven equilibrium (MSDE) preparation with a multi‐echo spoiled gradient‐echo sequence (SPGR) to suppress the blood signal intensity in T2* mapping of carotid plaques and liver. Materials and Methods: The analytical solution of the Bloch equations for the multi‐echo SPGR sequence, with and without the MSDE preparation, was calculated to optimize sequence parameters. The sequence was implemented at 3 Tesla and T2* maps of carotid plaques and liver were first optimized for blood suppression, and then acquired from five healthy livers and six subjects with ultrasound‐identified carotid plaques. Results: Simulations and experimental data showed that the flip angle that gives maximal signal (Ernst angle) in the MSDE‐SPGR was greatly increased from that of pure SPGR. Robust blood suppression was obtained in the T2* maps of carotid plaques and liver, requiring suppression at a field of speed (FOS) of 30 cm/s in both the carotids and liver. Conclusion: MSDE provides a means to suppress the blood signal intensity in SPGR sequences. Tissue T2* maps can be obtained without the confounding effects originating from blood vessels. J. Magn. Reson. Imaging 2011;. © 2011 Wiley‐Liss, Inc.