Removal of olefinic fat chemical shift artifact in diffusion MRI |
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Authors: | D C Karampinos K F King J P Haldar S Majumdar J G Georgiadis Z‐P Liang |
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Institution: | 1. Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana‐Champaign, Urbana, Illinois, USA;2. Department of Mechanical Science and Engineering, University of Illinois at Urbana‐Champaign, Urbana, Illinois, USA;3. Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California, USAThe first two authors contributed equally to this work.;4. Applied Science Laboratory, GE Healthcare, Waukesha, Wisconsin, USA;5. Department of Electrical and Computer Engineering, University of Illinois at Urbana‐Champaign, Urbana, Illinois, USA;6. Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California, USA |
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Abstract: | Diffusion‐weighted (DW) MRI has emerged as a key tool for assessing the microstructure of tissues in healthy and diseased states. Because of its rapid acquisition speed and insensitivity to motion, single‐shot echo‐planar imaging is the most common DW imaging technique. However, the presence of fat signal can severely affect DW‐echo planar imaging acquisitions because of the chemical shift artifact. Fat suppression is usually achieved through some form of chemical shift‐based fat saturation. Such methods effectively suppress the signal originating from aliphatic fat protons, but fail to suppress the signal from olefinic protons. Olefinic fat signal may result in significant distortions in the DW images, which bias the subsequently estimated diffusion parameters. This article introduces a method for removing olefinic fat signal from DW images, based on an echo time‐shifted acquisition. The method is developed and analyzed specifically in the context of single‐shot DW‐echo‐planar imaging, where image phase is generally unreliable. The proposed method is tested with phantom and in vivo datasets, and compared with a standard acquisition to demonstrate its performance. Magn Reson Med, 2011. © 2010 Wiley‐Liss, Inc. |
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Keywords: | olefinic protons diffusion EPI water/fat imaging |
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