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Decomposition of inflow and blood oxygen level‐dependent (BOLD) effects with dual‐echo spiral gradient‐recalled echo (GRE) fMRI
Author(s) -
Glover Gary H.,
Lemieux Susan K.,
Drangova Maria,
Pauly John M.
Publication year - 1996
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.1910350306
Subject(s) - echo (communications protocol) , spiral (railway) , gradient echo , inflow , blood oxygen level dependent , nuclear magnetic resonance , imaging phantom , signal (programming language) , spin echo , physics , magnetic resonance imaging , computer science , mathematics , medicine , radiology , mathematical analysis , optics , computer network , programming language , mechanics
Image contrast with gradient‐recalled echo sequences (GRE) used for fMRI can have both blood oxygen level‐dependent (BOLD) and inflow components, and the latter is often undesirable. A dual‐echo technique can be used to differentiate these mechanisms, because modulation of signal from inflow is common to both echoes, whereas susceptibility and diffusion‐related signal losses are larger in the second echo. An efficient dual‐echo interleaved spiral sequence was developed for use with a conventional scanner. It uses a κ‐space trajectory that spirals out from the origin while the first echo is collected, then spirals back in while collecting the second echo. Decomposition of the data provides separate images of the inflow and T 2 *‐weighted components. Results demonstrate the decomposition with phantom experiments and with photic stimulation in normal volunteers.