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Design of a nested eight-channel sodium and four-channel proton coil for 7T knee imaging

Authors

  • Ryan Brown,

    Corresponding author
    1. Department of Radiology, Bernard and Irene Schwartz Center for Biomedical Imaging, New York University Langone Medical Center, New York, New York, USA
    • Bernard and Irene Schwartz Center for Biomedical Imaging, New York University Langone Medical Center, 660 First Avenue, Fourth Floor, Room 401, New York, NY 10016
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  • Guillaume Madelin,

    1. Department of Radiology, Bernard and Irene Schwartz Center for Biomedical Imaging, New York University Langone Medical Center, New York, New York, USA
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  • Riccardo Lattanzi,

    1. Department of Radiology, Bernard and Irene Schwartz Center for Biomedical Imaging, New York University Langone Medical Center, New York, New York, USA
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  • Gregory Chang,

    1. Department of Radiology, Bernard and Irene Schwartz Center for Biomedical Imaging, New York University Langone Medical Center, New York, New York, USA
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  • Ravinder R. Regatte,

    1. Department of Radiology, Bernard and Irene Schwartz Center for Biomedical Imaging, New York University Langone Medical Center, New York, New York, USA
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  • Daniel K. Sodickson,

    1. Department of Radiology, Bernard and Irene Schwartz Center for Biomedical Imaging, New York University Langone Medical Center, New York, New York, USA
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  • Graham C. Wiggins

    1. Department of Radiology, Bernard and Irene Schwartz Center for Biomedical Imaging, New York University Langone Medical Center, New York, New York, USA
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Abstract

The critical design aim for a sodium/proton coil is to maximize sodium sensitivity and transmit field homogeneity while simultaneously providing adequate proton sensitivity and homogeneity. While most dual-frequency coils use lossy high-impedance trap circuits or PIN diodes to allow dual-resonance, we explored a nested-coil design for sodium/proton knee imaging at 7 T. A stand-alone eight-channel sodium receive array was implemented without standard dual-resonance circuitry to provide improved sodium signal-to-noise ratio. A detunable sodium birdcage was added for homogeneous sodium excitation and a four-channel proton transmit-receive array was added to provide anatomical reference imaging and B0 shimming capabilities. Both additional modules were implemented with minimal disturbance to the eight-channel sodium array by managing their respective resonances and geometrical arrangement. In vivo sodium signal-to-noise ratio was 1.2–1.7 times greater in the developed eight-channel array than in a mononuclear sodium birdcage coil, whereas the developed four-channel proton array provided signal-to-noise ratio similar to that of a commercial mononuclear proton birdcage coil. Magn Reson Med, 2013. © 2012 Wiley Periodicals, Inc.

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