Scan time reduction for readout-segmented EPI using simultaneous multislice acceleration: Diffusion-weighted imaging at 3 and 7 Tesla

Robert Frost, Peter Jezzard, Gwenaëlle Douaud, Stuart Clare, David A. Porter, Karla L. Miller

Research output: Contribution to journalArticlepeer-review

49 Scopus citations

Abstract

Purpose Readout-segmented echo-planar imaging (rs-EPI) can provide high quality diffusion data because it is less prone to distortion and blurring artifacts than single-shot echo-planar imaging (ss-EPI), particularly at higher resolution and higher field. Readout segmentation allows shorter echo-spacing and echo train duration, resulting in reduced image distortion and blurring, respectively, in the phase-encoding direction. However, these benefits come at the expense of longer scan times because the segments are acquired in multiple repetitions times (TRs). This study shortened rs-EPI scan times by reducing the TR duration with simultaneous multislice acceleration. Methods The blipped-CAIPI method for slice acceleration with reduced g-factor SNR loss was incorporated into the diffusion-weighted rs-EPI sequence. The rs- and ss-EPI sequences were compared at a range of resolutions at both 3 and 7 Tesla in terms of image fidelity and diffusion postprocessing results. Results Slice-accelerated clinically useful trace-weighted images and tractography results are presented. Tractography analysis showed that the reduced artifacts in rs-EPI allowed better discrimination of tracts than ss-EPI. Conclusion Slice acceleration reduces rs-EPI scan times providing a practical alternative to diffusion-weighted ss-EPI with reduced distortion and high resolution. Magn Reson Med 74:136-149, 2015.

Original languageEnglish
Pages (from-to)136-149
Number of pages14
JournalMagnetic Resonance in Medicine
Volume74
Issue number1
DOIs
StatePublished - Jul 1 2015
Externally publishedYes

Keywords

  • blipped-CAIPI
  • diffusion MRI
  • distortion
  • readout-segmented EPI
  • simultaneous multislice
  • tractography

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