Combination of complex‐based and magnitude‐based multiecho water‐fat separation for accurate quantification of fat‐fraction |
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| Authors: | Huanzhou Yu Ann Shimakawa Catherine D G Hines Charles A McKenzie Gavin Hamilton Claude B Sirlin Jean H Brittain Scott B Reeder |
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| Institution: | 1. Applied Science Laboratory, GE Healthcare, Menlo Park, California, USA;2. Department of Radiology, University of Wisconsin, Madison, Wisconsin, USA;3. Department of Biomedical Engineering, University of Wisconsin, Madison, Wisconsin, USA;4. Department of Medical Biophysics, The University of Western Ontario, London, Ontario, Canada;5. Department of Physics, The University of Western Ontario, London, Ontario, Canada;6. Department of Biomedical Engineering, The University of Western Ontario, London, Ontario, Canada;7. Department of Radiology, University of California, San Diego, California, USA;8. Applied Science Laboratory, GE Healthcare, Madison, Wisconsin, USA;9. Department of Medical Physics, University of Wisconsin, Madison, Wisconsin, USA;10. Department of Medicine, University of Wisconsin, Madison, Wisconsin, USA |
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| Abstract: | Multipoint water–fat separation techniques rely on different water–fat phase shifts generated at multiple echo times to decompose water and fat. Therefore, these methods require complex source images and allow unambiguous separation of water and fat signals. However, complex‐based water–fat separation methods are sensitive to phase errors in the source images, which may lead to clinically important errors. An alternative approach to quantify fat is through “magnitude‐based” methods that acquire multiecho magnitude images. Magnitude‐based methods are insensitive to phase errors, but cannot estimate fat‐fraction greater than 50%. In this work, we introduce a water–fat separation approach that combines the strengths of both complex and magnitude reconstruction algorithms. A magnitude‐based reconstruction is applied after complex‐based water–fat separation to removes the effect of phase errors. The results from the two reconstructions are then combined. We demonstrate that using this hybrid method, 0–100% fat‐fraction can be estimated with improved accuracy at low fat‐fractions. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc. |
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| Keywords: | water– fat separation IDEAL eddy currents water– fat ambiguity magnitude‐based water– fat separation hepatic steatosis fat quantification |
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