Single-shot echo-planar imaging with Nyquist ghost compensation: interleaved dual echo with acceleration (IDEA) echo-planar imaging (EPI)

Benedikt A Poser, Markus Barth, Pål-Erik Goa, Weiran Deng, V Andrew Stenger

Research output: Contribution to journalArticleAcademicpeer-review

11 Citations (Scopus)

Abstract

Echo planar imaging (EPI) is most commonly used for blood oxygen level-dependent fMRI, owing to its sensitivity and acquisition speed. A major problem with EPI is Nyquist (N/2) ghosting, most notably at high field. EPI data are acquired under an oscillating readout gradient and hence vulnerable to gradient imperfections such as eddy current delays and off-resonance effects, as these cause inconsistencies between odd and even k-space lines after time reversal. We propose a straightforward and pragmatic method herein termed "interleaved dual echo with acceleration (IDEA) EPI": two k-spaces (echoes) are acquired under the positive and negative readout lobes, respectively, by performing phase encoding blips only before alternate readout gradients. From these two k-spaces, two almost entirely ghost free images per shot can be constructed, without need for phase correction. The doubled echo train length can be compensated by parallel imaging and/or partial Fourier acquisition. The two k-spaces can either be complex averaged during reconstruction, which results in near-perfect cancellation of residual phase errors, or reconstructed into separate images. We demonstrate the efficacy of IDEA EPI and show phantom and in vivo images at both 3 T and 7 T.

Original languageEnglish
Pages (from-to)37-47
Number of pages11
JournalMagnetic Resonance in Medicine
Volume69
Issue number1
DOIs
Publication statusPublished - Jan 2013
Externally publishedYes

Keywords

  • Artifacts
  • Echo-Planar Imaging
  • Humans
  • Image Enhancement
  • Phantoms, Imaging

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