Premium
3D single‐shot VASO using a maxwell gradient compensated GRASE sequence
Author(s) -
Poser Benedikt A.,
Norris David G.
Publication year - 2009
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.22000
Subject(s) - nuclear magnetic resonance , signal (programming language) , magnetic resonance imaging , single shot , functional magnetic resonance imaging , visual cortex , neuroscience , physics , chemistry , computer science , psychology , optics , medicine , radiology , programming language
Abstract The vascular space occupancy (VASO) method was recently proposed as a functional MRI (fMRI) method that is capable of detecting activation‐related changes in blood volume (CBV), without the need for a blood‐pool contrast agent. In the present work we introduce a new whole‐brain VASO technique that is based on a parallel‐accelerated single‐shot 3D GRASE (gradient and spin echo) readout. The GRASE VASO sequence employs a flow‐compensated correction scheme for concomitant Maxwell gradients which is necessary to avoid smearing artifacts that may occur due to violation of the Carr–Purcell–Meiboom–Gill (CPMG) condition for off‐resonance excitation. Experiments with 6 min of visual‐motor stimulation were performed on eight subjects. At P < 0.01, average percent signal change and t ‐score for visual stimulation were −3.11% and −8.42, respectively; activation in left and right motor cortices and supplementary motor area was detected with −2.75% and −6.70, respectively. Sensitivity and signal changes are comparable to those of echo‐planar imaging (EPI)‐based single‐slice VASO, as indicated by additional visual‐task experiments (−3.39% and −6.93). The method makes it possible to perform whole‐brain cognitive activation studies based on CBV contrast. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.