3D single-shot VASO using a Maxwell gradient compensated GRASE sequence

Benedikt A Poser, David G Norris

Research output: Contribution to journalArticleAcademicpeer-review

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.

Original languageEnglish
Pages (from-to)255-62
Number of pages8
JournalMagnetic Resonance in Medicine
Volume62
Issue number1
DOIs
Publication statusPublished - Jul 2009
Externally publishedYes

Keywords

  • Algorithms
  • Evoked Potentials, Motor
  • Humans
  • Image Enhancement
  • Image Interpretation, Computer-Assisted
  • Imaging, Three-Dimensional
  • Magnetic Resonance Imaging
  • Motor Cortex
  • Reproducibility of Results
  • Sensitivity and Specificity

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