Implementation and assessment of diffusion-weighted partial Fourier readout-segmented echo-planar imaging

Frost, R., Porter, D. A., Miller, K. L. and Jezzard, P. (2012) Implementation and assessment of diffusion-weighted partial Fourier readout-segmented echo-planar imaging. Magnetic Resonance in Medicine, 68(2), pp. 441-451. (doi: 10.1002/mrm.23242) (PMID:22535706)

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Abstract

Single‐shot echo‐planar imaging has been used widely in diffusion magnetic resonance imaging due to the difficulties in correcting motion‐induced phase corruption in multishot data. Readout‐segmented EPI has addressed the multishot problem by introducing a two‐dimensional nonlinear navigator correction with online reacquisition of uncorrectable data to enable acquisition of high‐resolution diffusion data with reduced susceptibility artifact and T*2 blurring. The primary shortcoming of readout‐segmented EPI in its current form is its long acquisition time (longer than similar resolution single‐shot echo‐planar imaging protocols by approximately the number of readout segments), which limits the number of diffusion directions. By omitting readout segments at one side of k‐space and using partial Fourier reconstruction, readout‐segmented EPI imaging times could be reduced. In this study, the effects of homodyne and projection onto convex sets reconstructions on estimates of the fractional anisotropy, mean diffusivity, and diffusion orientation in fiber tracts and raw T2‐ and trace‐weighted signal are compared, along with signal‐to‐noise ratio results. It is found that projections onto convex sets reconstruction with 3/5 segments in a 2 mm isotropic diffusion tensor image acquisition and 9/13 segments in a 0.9 × 0.9 × 4.0 mm3 diffusion‐weighted image acquisition provide good fidelity relative to the full k‐space parameters. This allows application of readout‐segmented EPI to tractography studies, and clinical stroke and oncology protocols.

Item Type:Articles
Additional Information:Grant sponsor: Medical Research Council.
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Porter, Professor David
Authors: Frost, R., Porter, D. A., Miller, K. L., and Jezzard, P.
College/School:College of Medical Veterinary and Life Sciences > School of Psychology & Neuroscience
Journal Name:Magnetic Resonance in Medicine
Publisher:Wiley
ISSN:0740-3194
ISSN (Online):1522-2594
Published Online:28 December 2011

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