Comparison of spiral-in/out and spiral-out BOLD fMRI at 1.5 and 3 T

Neuroimage. 2004 Jan;21(1):291-301. doi: 10.1016/j.neuroimage.2003.09.017.

Abstract

Spiral-in/out functional magnetic resonance imaging (fMRI) methods acquire one image before the echo time (TE) and a second image after TE during each scan. Weighted combination of the two images provides a time series with reduced susceptibility dropout in frontal and medial temporal regions as well as increased signal-to-noise ratio (SNR) in regions of uniform cortex. In this study, task activation with the spiral-in/out method was compared to that with conventional spiral-out acquisitions at two field strengths (1.5 and 3.0 T) using episodic memory encoding, verbal working memory, and affective processing tasks in eight human volunteers. With the conventional spiral-out sequence, greater signal dropout is observed in lateral and medial prefrontal, amygdalar, and medial temporal regions at 3 T relative to 1.5 T, whereas such dropout at 3 T is reduced or mitigated with the spiral-in/out method. Similarly, activation volumes for frontal, amygdalar, and medial temporal regions are reduced for spiral-out acquisitions relative to spiral-in/out, and this difference is more apparent at 3 T than at 1.5 T. In addition, significant regionally specific increases in Z scores are obtained with the spiral-in/out sequence relative to spiral-out acquisitions at both field strengths. It is concluded the spiral-in/out sequence may provide significant advantages over conventional spiral methods, especially at 3 T.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Affect / physiology
  • Amygdala / physiology*
  • Artifacts
  • Attention / physiology
  • Brain Mapping
  • Color Perception / physiology
  • Discrimination Learning / physiology
  • Female
  • Humans
  • Image Enhancement / methods*
  • Image Processing, Computer-Assisted / methods*
  • Magnetic Resonance Imaging / methods*
  • Male
  • Memory, Short-Term / physiology
  • Nerve Net / physiology
  • Oxygen / blood*
  • Pattern Recognition, Visual / physiology
  • Prefrontal Cortex / physiology*
  • Temporal Lobe / physiology*
  • Verbal Learning / physiology

Substances

  • Oxygen