Correction for EPI distortions using multi-echo gradient-echo imaging

Magn Reson Med. 1999 Jun;41(6):1206-13. doi: 10.1002/(sici)1522-2594(199906)41:6<1206::aid-mrm17>3.0.co;2-l.

Abstract

A novel and effective technique is described for distortion correction in echo planar imaging (EPI) utilizing the field maps derived from multi-echo gradient-echo images. The distortions from different off-resonance related factors such as field inhomogeneity, eddy current effect, radiofrequency pulse frequency offset, and chemical shift effect can be simultaneously reduced to a great extent. With the proposed post-processing algorithm of multi-channel modulation, distortions may be corrected without unwrapping the phase discontinuities in the derived field map, a process that usually restricts the application of other field map-based correction methods. Results from phantom and animal experiments at 4.7 T demonstrate the efficiency of the method in reducing the geometrical distortions in gradient-echo EPI.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Algorithms
  • Animals
  • Brain / anatomy & histology
  • Echo-Planar Imaging / methods*
  • Humans
  • Image Processing, Computer-Assisted / methods
  • Magnetic Resonance Imaging / methods
  • Phantoms, Imaging
  • Rabbits