Improved reduction of motion artifacts in diffusion imaging using navigator echoes and velocity compensation

Clark, C. A., Barker, G. J. and Tofts, P. S. (2000) Improved reduction of motion artifacts in diffusion imaging using navigator echoes and velocity compensation. J Magn Reson, 142 (2). pp. 358-63. ISSN 1090-7807 (Print)

Abstract

Navigator echoes provide a means with which to remove motion artifacts from diffusion-weighted images obtained using any multishot imaging technique. However, residual motion artifact is often present in the corrected images rendering the technique unreliable. It is shown that velocity-compensated diffusion sensitization when used in tandem with a navigator echo further reduces the degree of residual motion artifacts present in the corrected images and improves the reliability and clinical utility of the technique. This is demonstrated by applying a method for quantification of motion artifact to brain images of healthy volunteers scanned using both conventional (Stejskal-Tanner) and velocity-compensated gradient sensitization. Other factors affecting the efficacy of the navigator echo technique, such as brain pulsatile motion, gradient b factor, and navigator echo signal-to-noise ratio, are also discussed.

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