Prevention of motion-induced signal loss in diffusion-weighted echo-planar imaging by dynamic restoration of gradient moments

Kazim Gumus*, Brian Keating, Benedikt A Poser, Brian Armstrong, Linda Chang, Julian Maclaren, Thomas Prieto, Oliver Speck, Maxim Zaitsev, Thomas Ernst

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

16 Citations (Web of Science)

Abstract

PURPOSE: Head motion is a significant problem in diffusion-weighted imaging as it may cause signal attenuation due to residual dephasing during strong diffusion encoding gradients even in single-shot acquisitions. Here, we present a new real-time method to prevent motion-induced signal loss in DWI of the brain.

METHODS: The method requires a fast motion tracking system (optical in the current implementation). Two alterations were made to a standard diffusion-weighted echo-planar imaging sequence: first, real-time motion correction ensures that slices are correctly aligned relative to the moving brain. Second, the tracking data are used to calculate the motion-induced gradient moment imbalance which occurs during the diffusion encoding periods, and a brief gradient blip is inserted immediately prior to the signal readout to restore the gradient moment balance.

RESULTS: Phantom experiments show that the direction as well as magnitude of the gradient moment imbalance affects the characteristics of unwanted signal attenuation. In human subjects, the addition of a moment-restoring blip prevented signal loss and improved the reproducibility and reliability of diffusion tensor measures even in the presence of substantial head movements.

CONCLUSION: The method presented can improve robustness for clinical routine scanning in populations that are prone to head movements, such as children and uncooperative adult patients.

Original languageEnglish
Pages (from-to)2006-2013
Number of pages8
JournalMagnetic Resonance in Medicine
Volume71
Issue number6
DOIs
Publication statusPublished - Jun 2014
Externally publishedYes

Keywords

  • Diffusion Magnetic Resonance Imaging
  • Echo-Planar Imaging
  • Head Movements
  • Healthy Volunteers
  • Humans
  • Image Processing, Computer-Assisted
  • Motion
  • Phantoms, Imaging
  • Reproducibility of Results
  • Signal Processing, Computer-Assisted

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