Full Paper

Experimental determination of human peripheral nerve stimulation thresholds in a 3-axis planar gradient system

  1. Rebecca E. Feldman,
  2. Christopher J. Hardy,
  3. Bulent Aksel,
  4. John Schenck,
  5. Blaine A. Chronik*

Article first published online: 12 JUN 2009

DOI: 10.1002/mrm.22050

Issue

Magnetic Resonance in Medicine

Magnetic Resonance in Medicine

Volume 62, Issue 3, pages 763–770, September 2009

Additional Information

How to Cite

Feldman, R. E., Hardy, C. J., Aksel, B., Schenck, J. and Chronik, B. A. (2009), Experimental determination of human peripheral nerve stimulation thresholds in a 3-axis planar gradient system. Magn Reson Med, 62: 763–770. doi: 10.1002/mrm.22050

Author Information

  1. Medical Biophysics, UWO, GE Global Research, Niskayuna, NY, Physics and Astronomy, University of Western Ontario, London, Ontario, Canada

*Department of Physics and Astronomy, University of Western Ontario, 1151 Richmond Street, London, Ontario, Canada, N6A 3K7

Publication History

  1. Issue published online: 26 AUG 2009
  2. Article first published online: 12 JUN 2009
  3. Manuscript Accepted: 26 MAR 2009
  4. Manuscript Revised: 25 FEB 2009
  5. Manuscript Received: 8 OCT 2008

Funded by

  • National Institutes of Health. Grant Number: R01 RR15396

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Keywords:

  • planar gradients;
  • gradient systems;
  • magnetic resonance imaging;
  • peripheral nerve stimulation

Abstract

In MRI, strong, rapidly switched gradient fields are desirable because they can be used to reduce imaging time, obtain images with better resolution, or improve image signal-to-noise ratios. Improvements in gradient strength can be made by either increasing the gradient amplifier strength or by enhancing gradient efficiency. Unfortunately, many MRI pulse sequences, in combination with high-performance amplifiers and existing gradient hardware, can cause peripheral nerve stimulation (PNS). This makes improvements in gradient amplifiers ineffective at increasing safely usable gradient strength. Customized gradient coils are one way to achieve significant improvements in gradient performance. One specific gradient configuration, a planar gradient system, promises improved gradient strength and switching time for cardiac imaging. The PNS thresholds for planar gradients were characterized through human stimulation experiments on all three gradient axes. The specialized gradient was shown to have significantly higher stimulation thresholds than traditional cylindrical designs (y-axis SRmin = 210 ± 18 mT/m/ms and ΔGmin = 133 ± 13 mT/m; x-axis SRmin = 222 ± 24 mT/m/ms and ΔGmin = 147 ± 17 mT/m; z-axis SRmin = 252 ± 26 mT/m/ms and ΔGmin = 218 ± 26 mT/m). This system could be operated at gradient strengths 2 to 3 times higher than cylindrical configurations without causing stimulation. Magn Reson Med, 2009. © 2009 Wiley-Liss, Inc.

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