Sampling and reconstruction effects due to motion in diffusion-weighted interleaved echo planar imaging

Atkinson, D., Porter, D. A., Hill, D. L.G., Calamante, F. and Connelly, A. (2000) Sampling and reconstruction effects due to motion in diffusion-weighted interleaved echo planar imaging. Magnetic Resonance in Medicine, 44(1), pp. 101-109. (doi: 10.1002/1522-2594(200007)44:1<101::AID-MRM15>3.0.CO;2-S)

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Abstract

Subject motion during diffusion‐weighted interleaved echo‐planar imaging causes k‐space offsets which lead to irregular sampling in the phase‐encode direction. For each image, the k‐space shifts are monitored using 2D navigator echoes, and are shown to lead to a frequent violation of the Nyquist condition when an ungated sequence is used on seven subjects. Combining data from four repeat acquisitions allows the Nyquist condition to be satisfied in all but 1% of images. Reconstruction of the irregularly‐sampled data can be performed using a matrix inversion technique. The repeated acquisitions make the inversion more stable and additionally improve the signal‐to‐noise ratio. The resultant isotropic diffusion‐weighted images and average apparent diffusion coefficient (ADC) maps show high resolution and enable clear localization of a stroke lesion. Residual ADC artifacts with a slow spatial variation are observed and assumed to originate from non‐rigid pulsatile brain motion.

Item Type:Articles
Additional Information:Grant sponsor: UK Engineering and Physical Sciences Research Council; Grant number: GR/L32965; Grant sponsor: The Wellcome Trust.
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Porter, Professor David
Authors: Atkinson, D., Porter, D. A., Hill, D. L.G., Calamante, F., and Connelly, A.
College/School:College of Medical Veterinary and Life Sciences > Institute of Neuroscience and Psychology
Journal Name:Magnetic Resonance in Medicine
Publisher:Wiley
ISSN:0740-3194
ISSN (Online):1522-2594

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