Get 20M+ Full-Text Papers For Less Than $1.50/day. Start a 7-Day Trial for You or Your Team.

Learn More →

Centric ordering is superior to gradient moment nulling for motion artifact reduction in EPI

Centric ordering is superior to gradient moment nulling for motion artifact reduction in EPI Echo‐planar imaging (EPI) is sensitive to motion despite its rapid data acquisition rate. Compared with traditional imaging techniques, it is more sensitive to motion or flow in the phase‐encode direction, which can cause image artifacts such as ghosting, misregistration, and loss of spatial resolution. Consequently, EPI of dynamic structures (eg, the cardiovascular system) could benefit from methods that eliminate these artifacts. In this paper, two methods of artifact reduction for motion in the phase‐encode direction are evaluated. First, the k‐space trajectory is evaluated by comparing centric with top‐down ordered sequences. Next, velocity gradient moment nulling (GMN) of the phase‐encode direction is evaluated for each trajectory. Computer simulations and experiments in flow phantoms and rabbits in vivo show that uncompensated centric ordering produces the highest image quality. This is probably due to a shorter readout duration, which reduces T2* relaxation losses and off‐resonance effects, and to the linear geometry of phantoms and vessels, which can obscure centric blurring artifacts. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Journal of Magnetic Resonance Imaging Wiley

Centric ordering is superior to gradient moment nulling for motion artifact reduction in EPI

Download PDF
10 pages

Loading next page...
 
/lp/wiley/centric-ordering-is-superior-to-gradient-moment-nulling-for-motion-FbdeeLYBip

References (24)

Publisher
Wiley
Copyright
Copyright © 1997 Wiley‐Liss, Inc., A Wiley Company
ISSN
1053-1807
eISSN
1522-2586
DOI
10.1002/jmri.1880070627
Publisher site
See Article on Publisher Site

Abstract

Echo‐planar imaging (EPI) is sensitive to motion despite its rapid data acquisition rate. Compared with traditional imaging techniques, it is more sensitive to motion or flow in the phase‐encode direction, which can cause image artifacts such as ghosting, misregistration, and loss of spatial resolution. Consequently, EPI of dynamic structures (eg, the cardiovascular system) could benefit from methods that eliminate these artifacts. In this paper, two methods of artifact reduction for motion in the phase‐encode direction are evaluated. First, the k‐space trajectory is evaluated by comparing centric with top‐down ordered sequences. Next, velocity gradient moment nulling (GMN) of the phase‐encode direction is evaluated for each trajectory. Computer simulations and experiments in flow phantoms and rabbits in vivo show that uncompensated centric ordering produces the highest image quality. This is probably due to a shorter readout duration, which reduces T2* relaxation losses and off‐resonance effects, and to the linear geometry of phantoms and vessels, which can obscure centric blurring artifacts.

Journal

Journal of Magnetic Resonance Imaging – Wiley

Published: Nov 1, 1997

There are no references for this article.