## Abstract In 3D MRI, sampling __k__‐space with traditional trajectories can be excessively time‐consuming. Fast imaging trajectories are used in an attempt to efficiently cover the __k__‐space and reduce the scan time without significantly affecting the image quality. In many applications, furthe
k-space undersampling in PROPELLER imaging
✍ Scribed by Konstantinos Arfanakis; Ashish A. Tamhane; James G. Pipe; Mark A. Anastasio
- Publisher
- John Wiley and Sons
- Year
- 2005
- Tongue
- English
- Weight
- 951 KB
- Volume
- 53
- Category
- Article
- ISSN
- 0740-3194
No coin nor oath required. For personal study only.
✦ Synopsis
Abstract
PROPELLER MRI (periodically rotated overlapping parallel lines with enhanced reconstruction) provides images with significantly fewer B~0~‐related artifacts than echo‐planar imaging (EPI), as well as reduced sensitivity to motion compared to conventional multiple‐shot fast spin‐echo (FSE). However, the minimum imaging time in PROPELLER is markedly longer than in EPI and 50% longer than in conventional multiple‐shot FSE. Often in MRI, imaging time is reduced by undersampling k‐space. In the present study, the effects of undersampling on PROPELLER images were evaluated using simulated and in vivo data sets. Undersampling using PROPELLER patterns with reduced number of samples per line, number of lines per blade, or number of blades per acquisition, while maintaining the same k‐space field of view (FOV~k~) and uniform sampling at the edges of FOV~k~, reduced imaging time but led to severe image artifacts. In contrast, undersampling by means of removing whole blades from a PROPELLER sampling pattern that sufficiently samples k‐space produced only minimal image artifacts, mainly manifested as blurring in directions parallel to the blades removed, even when reducing imaging time by as much as 50%. Finally, undersampling using asymmetric blades and taking advantage of Hermitian symmetries to fill‐in the missing data significantly reduced imaging time without causing image artifacts. Magn Reson Med 53:675–683, 2005. © 2005 Wiley‐Liss, Inc.
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