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Simultaneous spin‐echo refocusing
Author(s) -
Günther Matthias,
Feinberg David A.
Publication year - 2005
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.20587
Subject(s) - spin echo , artifact (error) , image quality , phase (matter) , physics , nuclear magnetic resonance , multislice , flip angle , echo (communications protocol) , pulse sequence , signal (programming language) , computer science , optics , image (mathematics) , magnetic resonance imaging , artificial intelligence , medicine , computer network , quantum mechanics , radiology , programming language
A new approach to spin‐echo imaging is presented in which the 180° RF pulse refocuses two or more spin‐echoes at different positions in the readout period. When simultaneous echo refocusing (SER) is implemented using multiple 180° pulses, an undesirable mixing of stimulated echoes and primary echoes from different slices can occur. A novel periodic gradient spoiler scheme eliminates this potential source of artifacts without spoiling the correctly timed stimulated echoes, which, similar to RARE (TSE) sequences, add coherently to the primary echoes. Comparisons show equivalent artifact elimination using phase cycling, periodic spoiling, and a previously developed spoiling scheme for non‐Carr–Purcell–Meiboom–Gill sequences. A comparison of head images at 1.5 T acquired with SER‐TSE and conventional TSE T 1 ‐weighted sequences show no degradation in image quality nor SNR. T 2 ‐weighted imaging is not achievable with the current implementation, but possible solutions are proposed. The proposed technique might prove especially beneficial at higher field strengths, where the reduced number of refocusing pulses for multislice SER‐TSE decreases RF power deposition. SER spin‐echo imaging offers an approach that is very different from low flip angle imaging to mitigate RF heating limitations in high‐field clinical imaging. Magn Reson Med, 2005. © 2005 Wiley‐Liss, Inc.