Non-water-suppressed proton MR spectroscopy improves spectral quality in the human spinal cord

Authors

  • Andreas Hock,

    Corresponding author
    1. Departament of Information Technology and Electrical Engineering, University and ETH Zurich, Zurich, Switzerland
    • Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland
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  • Erin L. MacMillan,

    1. Departament of Information Technology and Electrical Engineering, University and ETH Zurich, Zurich, Switzerland
    2. Department of Clinical Research and Institute of Diagnostic, Interventional and Pediatric Radiology, University of Bern, Bern, Switzerland
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  • Alexander Fuchs,

    1. Departament of Information Technology and Electrical Engineering, University and ETH Zurich, Zurich, Switzerland
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  • Roland Kreis,

    1. Department of Clinical Research and Institute of Diagnostic, Interventional and Pediatric Radiology, University of Bern, Bern, Switzerland
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  • Peter Boesiger,

    1. Departament of Information Technology and Electrical Engineering, University and ETH Zurich, Zurich, Switzerland
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  • Spyros S. Kollias,

    1. Institute of Neuroradiology, University Hospital of Zurich, Zurich, Switzerland
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  • Anke Henning

    1. Departament of Information Technology and Electrical Engineering, University and ETH Zurich, Zurich, Switzerland
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Abstract

Magnetic resonance spectroscopy enables insight into the chemical composition of spinal cord tissue. However, spinal cord magnetic resonance spectroscopy has rarely been applied in clinical work due to technical challenges, including strong susceptibility changes in the region and the small cord diameter, which distort the lineshape and limit the attainable signal to noise ratio. Hence, extensive signal averaging is required, which increases the likelihood of static magnetic field changes caused by subject motion (respiration, swallowing), cord motion, and scanner-induced frequency drift. To avoid incoherent signal averaging, it would be ideal to perform frequency alignment of individual free induction decays before averaging. Unfortunately, this is not possible due to the low signal to noise ratio of the metabolite peaks. In this article, frequency alignment of individual free induction decays is demonstrated to improve spectral quality by using the high signal to noise ratio water peak from non-water-suppressed proton magnetic resonance spectroscopy via the metabolite cycling technique. Electrocardiography (ECG)-triggered point resolved spectroscopy (PRESS) localization was used for data acquisition with metabolite cycling or water suppression for comparison. A significant improvement in the signal to noise ratio and decrease of the Cramér Rao lower bounds of all metabolites is attained by using metabolite cycling together with frequency alignment, as compared to water-suppressed spectra, in 13 healthy volunteers. Magn Reson Med, 2013. © 2012 Wiley Periodicals, Inc.

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