Chinese Journal of Magnetic Resonance

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Respiration-Induced Artifacts and Navigator Echo Correction in Gradient Echo Imaging on Human Brain

DONG Fang,PEI Meng-chao,WANG Qian-feng,JIANG Hong-wei,LI Jian-qi*   

  1. Shanghai Key Laboratory of Magnetic Resonance, Department of Physics, East China Normal University, Shanghai 200062, China
  • Received:2013-08-12 Revised:2014-07-18 Online:2014-09-05 Published:2014-09-05
  • About author:LI Jian-qi, Tel: 021-62223871, E-mail: jqli@phy.ecnu.edu.cn.
  • Supported by:

    国家自然科学基金资助项目(81271533).

Abstract:

Images acquired with gradient echo sequences are susceptible to artifacts induced by frequency offsets varying in spatial and temporal dimensions. This study addressed how respiration-induced local field fluctuations affect the quality of brain images acquired with a three-dimensional multi-echo gradient echo sequence. It was shown that respiration-related artifacts can be corrected by acquire a one-dimensional navigator signal before the application of phase-encoding gradient in each phase-encoding step, which later can be used to correct respiration-related phase shifts during reconstruction to yield
artifact-free images. Experimental results showed that both the respiration-related phase oscillations and image artifacts increased with echo time. It was also demonstrated that the phase fluctuations and image artifact levels in both the gradient echo images and T2* maps calculated from mutli-echo data reduced significantly after navigator echo phase correction.

Key words: MRI, respiratory induced artifacts, navigator echo, gradient echo, T2* mapping

CLC Number: