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Comparison of the threshold for peripheral nerve stimulation during gradient switching in whole body MR systems
Author(s) -
Den Boer Jacques A.,
Bourland Joe D.,
Nyenhuis John A.,
Ham Cornelis L.G.,
Engels Johan M.L.,
Hebrank Franz X.,
Frese Georg,
Schaefer Daniel J.
Publication year - 2002
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.10110
Subject(s) - rheobase , peripheral nerve stimulation , physics , biomedical engineering , stimulation , peripheral , nuclear magnetic resonance , medicine , neuroscience , biology
Purpose: To compare thresholds for peripheral nerve stimulation from gradient switching in whole body magnetic resonance (MR) equipment of different design. Materials and Methods: Threshold data obtained in three experiments were reformatted into a single joint data set describing thresholds for anterio‐posterior (AP) gradient orientation and Echo Planar Imaging (EPI) waveforms with bipolar ramp times between 0.07 and 1.2 ms. Reformatting included the use of: a) the rate of change of the maximum field in the patient space as a measure of gradient output, b) lowest observable thresholds, c) lognormal distribution of thresholds, and d) equal standard deviation (SD) of all samples. Results: The joint data fit a hyperbolic threshold function. The residues were not significantly different between experiments. Conclusion: When expressed in appropriate format, the thresholds for peripheral nerve stimulation in volunteers for whole body MR equipment can be described with a hyperbolic threshold curve with rheobase 18.8 ± 0.6 Tesla/second and chronaxie 0.36 ± 0.02 milliseconds. J. Magn. Reson. Imaging 2002;15:520–525. © 2002 Wiley‐Liss, Inc.