Characterization and reduction of X-gradient induced eddy currents in a NdFeB magnetic resonance imaging magnet-3D finite element method-based numerical studies

Li, Xia, Xia, Ling, Liu, Feng, Crozier, Stuart and Xie, Dexin (2011) Characterization and reduction of X-gradient induced eddy currents in a NdFeB magnetic resonance imaging magnet-3D finite element method-based numerical studies. Concepts in Magnetic Resonance Part B: Magnetic Resonance Engineering, 39 B 1: 47-58. doi:10.1002/cmr.b.20189


Author Li, Xia
Xia, Ling
Liu, Feng
Crozier, Stuart
Xie, Dexin
Title Characterization and reduction of X-gradient induced eddy currents in a NdFeB magnetic resonance imaging magnet-3D finite element method-based numerical studies
Journal name Concepts in Magnetic Resonance Part B: Magnetic Resonance Engineering   Check publisher's open access policy
ISSN 1552-5031
1552-504X
Publication date 2011
Year available 2011
Sub-type Article (original research)
DOI 10.1002/cmr.b.20189
Volume 39 B
Issue 1
Start page 47
End page 58
Total pages 12
Place of publication Hoboken, NJ United States
Publisher John Wiley and Sons Inc.
Collection year 2013
Language eng
Subject 1606 Political Science
1607 Social Work
2741 Radiology Nuclear Medicine and imaging
3614 Radiological and Ultrasound Technology
Abstract In permanent magnetic resonance imaging (MRI) systems, pulsed gradient fields induce strong eddy currents in the conducting structures of the magnet. The gradient field for image encoding is perturbed by these eddy currents, thus leading to MR image distortions. The conventional approach for the reduction of the eddy current effects is to employ passive shielding (an eddy current board). However, the analysis of the passive shielding structure is typically nonoptimal. In this article, a comprehensive 3D finite element method (FEM) model for the characterization of eddy currents in the ferromagnetic materials of the magnet is developed, which is helpful for the evaluation of the shielding effects and the improvement of passive shielding designs. During the numerical analyses, the eddy current source was introduced through X-gradient coils, nonlinearity, and the anisotropy of the laminated silicon steel structure was considered, with the selection of a penalty factor in the FEM governing equations being also detailed. Based on the simulations results, suggestions have been made for passive shielding designs.
Keyword Eddy currents
Ferromagnetic materials
Finite element method
Gradient coil
Magnetic resonance imaging
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Information Technology and Electrical Engineering Publications
 
Versions
Version Filter Type
Citation counts: TR Web of Science Citation Count  Cited 0 times in Thomson Reuters Web of Science Article
Scopus Citation Count Cited 1 times in Scopus Article | Citations
Google Scholar Search Google Scholar
Created: Wed, 27 Nov 2013, 18:05:14 EST by System User on behalf of School of Information Technol and Elec Engineering