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Spectroscopic imaging using concentrically circular echo‐planar trajectories in vivo
Author(s) -
Furuyama Jon K.,
Wilson Neil E.,
Thomas M. Albert
Publication year - 2012
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.23184
Subject(s) - planar , concentric , imaging phantom , nuclear magnetic resonance , k space , echo planar imaging , physics , bandwidth (computing) , optics , gadolinium , echo (communications protocol) , image resolution , cartesian coordinate system , magnetic resonance imaging , chemistry , computer science , mathematics , geometry , fourier transform , medicine , computer network , computer graphics (images) , radiology , organic chemistry , quantum mechanics
An alternative to the standard echo‐planar spectroscopic imaging technique is presented, spectroscopic imaging using concentrically circular echo‐planar trajectories (SI‐CONCEPT). In contrast to the conventional chemical shift imaging data, the sampled data from each set of concentric rings were regridded into Cartesian space. Usage of concentric k ‐space trajectories has the advantage of requiring significantly reduced slew rates than echo‐planar spectroscopic imaging, allowing for the collection of higher spectral bandwidths and opening the door for high‐bandwidth echo‐planar styled spectroscopic imaging at higher magnetic fields. Before two‐dimensional spatial and one‐dimensional spectral encoding, the volume of interest was localized using the standard point‐resolved spectroscopy sequence. The feasibility of using concentric k ‐space trajectories is demonstrated, and the spatial profiles and representative spectra are compared with the standard echo‐planar spectroscopic imaging technique in a gray matter phantom containing metabolites at physiological concentrations and healthy human brain in vivo. The symmetric nature of the concentric circles also reduces the number of required excitations for a given resolution by a factor of two. Possible artifacts and limitations are discussed. Magn Reson Med, 2011. © 2011 Wiley Periodicals, Inc.