Concomitant magnetic-field-induced artifacts in axial echo planar imaging

Xiaohong Joe Zhou, Yiping P. Du, Matthew A Bernstein, H. Glenn Reynolds, Joseph K. Maier, Jason A. Polzin

Research output: Contribution to journalArticle

50 Scopus citations

Abstract

When a linear magnetic field gradient is used, spatially higher-order magnetic fields are produced to satisfy the Maxwell equations. It has been observed that the higher-order magnetic field produced by the readout gradient causes axial echo planar images acquired with a horizontal solenoid magnet to shift along the phase-encoding direction and lose image intensities. Both the shift and intensity reduction become increasingly severe as the slice offset from the isocenter increases. These phenomena are quantitatively analyzed, and good correlation between experiments and theory has been established. The analysis also predicts a previously unreported Nyquist ghost on images with very large slice offsets. This ghost has verified with computer simulations. Based on the analysis, several methods have developed to eliminate the image shift, the intensity reduction, and the ghost. Selected methods have been implemented on a commercial scanner and proved effective in removing these image artifacts.

Original languageEnglish (US)
Pages (from-to)596-605
Number of pages10
JournalMagnetic Resonance in Medicine
Volume39
Issue number4
DOIs
StatePublished - Apr 1998
Externally publishedYes

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Keywords

  • Concomitant magnetic field
  • Echo planar
  • Maxwell terms

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging
  • Radiological and Ultrasound Technology

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