Concomitant gradient field effects in spiral scans

Kevin F. King, Alexander Ganin, Xiaohong Joe Zhou, Matt A. Bernstein

Research output: Contribution to journalArticle

56 Scopus citations

Abstract

Maxwell's equations imply that imaging gradients are accompanied by higher order spatially varying fields (concomitant fields) that can cause artifacts in MR imaging. The lowest order concomitant fields depend quadratically on the imaging gradient amplitude and inversely on the static field strength. Time-varying concomitant fields that accompany the readout gradients of spiral scans cause unwanted phase accumulation during the readout, resulting in spatially dependent blurring. Concomitant field phase errors are independent of echo time and, therefore, cannot be detected using Dixon-type field map measurements that are normally used to deblur spiral scan images. Data acquisition methods that reduce concomitant field blurring increase off-resonant spin blurring, and vice versa. Blurring caused by concomitant fields can be removed by variations of image reconstruction methods developed to correct for spatially dependent resonance offsets with nonrectangular k-space trajectories.

Original languageEnglish (US)
Pages (from-to)103-112
Number of pages10
JournalMagnetic Resonance in Medicine
Volume41
Issue number1
DOIs
StatePublished - Feb 13 1999

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Keywords

  • Artifacts
  • Concomitant field
  • Spiral scanning

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging

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