Gradient preemphasis calibration in diffusion-weighted echo-planar imaging

Magn Reson Med. 2000 Oct;44(4):616-24. doi: 10.1002/1522-2594(200010)44:4<616::aid-mrm16>3.0.co;2-t.

Abstract

This article describes a method which enables fast and objective pulse-sequence-specific preemphasis calibration, using standard pulse sequences and system hardware. The method is based on a k-space measurement technique, and has been applied to single-shot, diffusion-weighted, spin-echo, echo-planar imaging (DW-SE-EPI), which is particularly sensitive to eddy-current-induced image distortions. The efficiency of the technique was demonstrated not only by the reduction of eddy-current fields to a negligible level using full preemphasis compensation, but also by the fact that adjustment of the slow time-base alone sufficed for the practical elimination of image distortions in the DW-SE-EPI images and the subsequent diffusion tensor maps (in a phantom and a human brain). By seeking to eliminate directly the effect of eddy-current-induced phase shifts during the EPI data collection, the method is free of the complications and restrictions associated with other eddy-current correction techniques for DW-SE-EPI (such as acquisition of additional calibration scans, intense postprocessing, extensive pulse-sequence modifications), making their use redundant.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Brain / anatomy & histology
  • Calibration
  • Echo-Planar Imaging* / instrumentation
  • Echo-Planar Imaging* / methods
  • Humans
  • Phantoms, Imaging