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International Journal of Antennas and Propagation
Volume 2008, Article ID 563196, 10 pages
http://dx.doi.org/10.1155/2008/563196
Research Article

Assessment of a PML Boundary Condition for Simulating an MRI Radio Frequency Coil

1Columbia University and New York State Psychiatric Institute, New York, NY 10032, USA
2University of Pittsburgh, Pittsburgh, PA 15260, USA
3University of Oklahoma, Norman, OK 73019-0390, USA

Received 16 October 2007; Revised 9 April 2008; Accepted 5 June 2008

Academic Editor: Stuart Crozier

Copyright © 2008 Yunsuo Duan et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Computational methods such as the finite difference time domain (FDTD) play an important role in simulating radiofrequency (RF) coils used in magnetic resonance imaging (MRI). The choice of absorbing boundary conditions affects the final outcome of such studies. We have used FDTD to assess the Berenger's perfectly matched layer (PML) as an absorbing boundary condition for computation of the resonance patterns and electromagnetic fields of RF coils. We first experimentally constructed a high-pass birdcage head coil, measured its resonance pattern, and used it to acquire proton ( 1 H ) phantom MRI images. We then computed the resonance pattern and B 1 field of the coil using FDTD with a PML as an absorbing boundary condition. We assessed the accuracy and efficiency of PML by adjusting the parameters of the PML and comparing the calculated results with measured ones. The optimal PML parameters that produce accurate (comparable to the experimental findings) FDTD calculations are then provided for the birdcage head coil operating at 127.72 MHz, the Larmor frequency of 1 H at 3 Tesla (T).