Detrimental effects of BOLD signal in arterial spin labeling fMRI at high field strength

Hanzhang Lu, Manus J. Donahue, Peter C M Van Zijl

Research output: Contribution to journalArticlepeer-review

72 Scopus citations

Abstract

Arterial spin labeling (ASL) MRI is a useful technique for noninvasive measurement of cerebral blood flow (CBF) in humans. High field strength provides a unique advantage for ASL because of longer blood T1 relaxation times, making this technique a promising quantitative approach for functional brain mapping. However, higher magnetic field also introduces new challenges. Here it is shown that the CBF response determined using ASL functional MRI (MRI) at 3.0 T contains significant contamination from blood-oxygenation-level- dependent (BOLD) effects. Due to interleaved acquisitions of label and control images, difference in blood oxygenation status between these two scans can cause incomplete cancellation of the static signal upon image subtraction, resulting in a BOLD-related artifact in the estimated CBF hemodynamics. If not accounted for, such an effect can complicate the interpretation of the ASL results, e.g., causing a delayed onset and offset of the response, or inducing an artifactual poststimulus undershoot. The BOLD contribution also decreases the sensitivity of ASL-based MRI. Correction methods are proposed to reduce the artifact, giving increased number of activated voxels (18 ± 5%, P = 0.006) and more accurate estimation of CBF temporal characteristics.

Original languageEnglish (US)
Pages (from-to)546-552
Number of pages7
JournalMagnetic resonance in medicine
Volume56
Issue number3
DOIs
StatePublished - Sep 2006

Keywords

  • ASL
  • Arterial spin labeling
  • Artifact
  • BOLD
  • Blood-oxygenation-level-dependent
  • CBF
  • Cerebral blood flow
  • Functional MRI
  • Hemodynamic response
  • fMRI

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging

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