Elsevier

NeuroImage

Volume 6, Issue 3, October 1997, Pages 156-167
NeuroImage

Regular Article
Anatomic Localization and Quantitative Analysis of Gradient Refocused Echo-Planar fMRI Susceptibility Artifacts

https://doi.org/10.1006/nimg.1997.0289Get rights and content

Abstract

Functional magnetic resonance imaging (fMRI) techniques, such as echo-planar imaging, can permit rapid, sensitive, whole-brain measurements of local blood flow-induced MR signal changes seen during cognitive paradigms. Changes in blood oxygenation due to mismatch of flow and oxygen metabolism cause dynamic variations in microscopic susceptibility effects, leading to the blood oxygenation level-dependent (BOLD) signal measured by fMRI techniques. A related static macroscopic susceptibility effect is known to cause artifacts that attenuate the MR signal, leading to “blind spots” in some regions of brain adjacent to bone and air sinuses. The anatomical location, spatial extent, and magnitude of signal loss artifact are quantitated for a common whole-brain fMRI technique. Resting gradient-echo EPI studies were obtained in four healthy volunteers. Signal loss was primarily localized to inferior frontal regions (medial orbital gyri and gyrus rectus) and to inferior lateral temporal lobe (including part of fusiform gyrus) bilaterally. Increased echo time (TE) uniformly produced larger artifacts. The orientation of acquired slices and choice of phase-encoding direction influenced the location, shape, and extent of the artifacts. Regions of the brain with severe artifact may have attenuated activation signal, with potential implications for the design and interpretation of fMRI studies targeting activations in these areas.

References (47)

  • M.S. Cohen et al.

    Ultra-fast imaging

    Magn. Reson. Imaging

    (1991)
  • I.R. Young et al.

    The benefits of increasing spatial resolution as a means of reducing artifacts due to field inhomogeneities

    Magn. Reson. Imaging

    (1988)
  • P.A. Bandettini et al.

    Time course EPI of human brain function during task activation

    Magn. Reson. Med.

    (1992)
  • P.A. Bandettini et al.

    Spin-echo and gradient-echo EPI of human brain activation using BOLD contrast: A comparative study at 1.5 T

    NMR Biomed.

    (1994)
  • J.R. Binder et al.

    Lateralized human brain language systems demonstrated by task subtraction functional magnetic resonance imaging

    Arch. Neurol.

    (1995)
  • A.M. Blamire et al.

    Dynamic mapping of the human visual cortex by high-speed magnetic resonance imaging

    Proc. Natl. Acad. Sci. USA

    (1992)
  • Z.H. Cho et al.

    Reduction of susceptibility artifact in gradient-echo imaging

    Magn. Reson. Med.

    (1992)
  • T.E. Conturo et al.

    Sensitivity optimization and experimental design in functional magnetic resonance imaging

    Soc. Neurosci. Abstr.

    (1996)
  • C.A. Cuenod et al.

    Functional MRI during word generation, using conventional equipment

    Neurology

    (1995)
  • L.F. Czervionke et al.

    Magnetic susceptibility artifacts in gradient-recalled echo MR imaging

    Am. J. Neuroradiol.

    (1988)
  • H. Damasio et al.

    A neural basis for lexical retrieval

    Nature

    (1996)
  • J.E. Desmond et al.

    Functional MRI measurement of language lateralization in Wada-tested patients

    Brain

    (1995)
  • F. Farzaneh et al.

    Analysis of T2 limitations and off-resonance effects on spatial resolution and artifacts in echo-planar imaging

    Magn. Reson. Med.

    (1990)
  • P.T. Fox et al.

    Focal physiological uncoupling of cerebral blood flow and oxidative metabolism during somatosensory stimulation in human subjects

    Proc. Natl. Acad. Sci. USA

    (1986)
  • P.T. Fox et al.

    Nonoxidative glucose consumption during focal physiologic neural activity

    Science

    (1988)
  • J. Frahm et al.

    Direct FLASH MR imaging of magnetic field inhomogeneities by gradient compensation

    Magn. Reson. Med.

    (1988)
  • J. Frahm et al.

    Dynamic MR imaging of human brain oxygenation during rest and photic stimulation

    J. Magn. Reson. Imaging

    (1992)
  • E.M. Haacke et al.

    Reduction of T2* dephasing in gradient field-echo imaging

    Radiology

    (1989)
  • J.V. Hajnal et al.

    Artifacts due to stimulus correlated motion in functional imaging of the brain

    Magn. Res. Med.

    (1994)
  • J.V. Haxby et al.

    The functional organization of human extrastriate cortesx: A PET-rCBF study of selective attention to faces and locations

    J. Neurosci.

    (1994)
  • J. Hennig et al.

    RARE imaging: A fast imaging method for clinical MR

    Magn. Reson. Med.

    (1986)
  • L. Hertz-Pannier et al.

    Comparison between echo planar imaging and a conventional gradient echo sequence (SPGR) in brain functional imaging

    Soc. Magn. Reson. Med. Abstr.

    (1993)
  • C.R. Jack et al.

    Sensory motor cortex: Correlation of presurgical mapping with functional MR imaging and invasive cortical mapping

    Radiology

    (1994)
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