Publication Type Academic Article
Authors Winkler S, Alejski A, Wade T, McKenzie C, Rutt B
Journal Magn Reson Med
Volume 78
Issue 4
Pagination 1635-1645
Date Published 11/17/2016
ISSN 1522-2594
Keywords Acoustics, Head, Magnetic Resonance Imaging, Models, Theoretical
Abstract PURPOSE: To accurately analyze vibroacoustics in MR head gradient coils. THEORY AND METHODS: A detailed theoretical model for gradient coil vibroacoustics, including the first description and modeling of Lorentz damping, is introduced and implemented in a multiphysics software package. Numerical finite-element method simulations were used to establish a highly accurate vibroacoustic model in head gradient coils in detail, including the newly introduced Lorentz damping effect. Vibroacoustic coupling was examined through an additional modal analysis. Thorough experimental studies were used to validate simulations. RESULTS: Average experimental sound pressure levels (SPLs) and accelerations over the 0-3000 Hz frequency range were 97.6 dB, 98.7 dB, and 95.4 dB, as well as 20.6 g, 8.7 g, and 15.6 g for the X-, Y-, and Z-gradients, respectively. A reasonable agreement between simulations and measurements was achieved. Vibroacoustic coupling showed a coupled resonance at 2300 Hz for the Z-gradient that is responsible for a sharp peak and the highest SPL value in the acoustic spectrum. CONCLUSION: We have developed and used more realistic multiphysics simulation methods to gain novel insights into the underlying concepts for vibroacoustics in head gradient coils, which will permit improved analyses of existing gradient coils and novel SPL reduction strategies for future gradient coil designs. Magn Reson Med 78:1635-1645, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
DOI 10.1002/mrm.26543
PubMed ID 27859549
PubMed Central ID PMC5435555
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