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Robust outer volume suppression utilizing elliptical pulsed second order fields (ECLIPSE) for human brain proton MRSI
Author(s) -
Kumaragamage Chathura,
De Feyter Henk M.,
Brown Peter,
McIntyre Scott,
Nixon Terence W.,
Graaf Robin A.
Publication year - 2020
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.28047
Subject(s) - eclipse , nuclear magnetic resonance , materials science , physics , astrophysics
Purpose The robust and reliable utilization of proton magnetic resonance spectroscopic imaging (MRSI) at high fields is hampered by several key technical difficulties, including contamination from extracranial lipids. To that end, this work presents novel lipid suppression sequences for proton MRSI in the human brain utilizing elliptical localization with pulsed second‐order fields (ECLIPSE). Methods Two lipid suppression methods were implemented with the ECLIPSE gradient insert. One method is a variable power, 4‐pulse sequence optimized to achieve outer volume suppression (OVS) and compared against a standard, 8‐slice OVS method. The second ECLIPSE method is implemented as an inversion recovery (IR) sequence with elliptical inner volume selection (IVS) and compared against a global IR method. Results The ECLIPSE‐OVS sequence provided a 116‐fold mean lipid suppression (range, 104–134), whereas an optimized 8‐slice OVS sequence achieved 15‐fold suppression (range, 13–18). Furthermore, the superior ECLIPSE‐OVS suppression was achieved at 30% of the radiofrequency (RF) power required by 8‐slice OVS. The ECLIPSE‐based IR sequence suppressed skull lipids by 155‐fold (range, 122–257), compared to 16‐fold suppression (range, 14–19) achieved with IR. Conclusion OVS and IVS executed with ECLIPSE provide robust and effective lipid suppression at reduced RF power with high immunity to variations in B 1 and T 1 .