In this paper, we present the design of probe excitations for 7- and 10.5-T traveling-wave wide-bore magnetic resonance imaging systems. The probes are 297- and 447-MHz coaxially fed microstrip patches, designed to give a circularly polarized magnetic field when placed in the metallic bore waveguide. Images of a water phantom using the patch probes are obtained and compared with full-wave electromagnetic simulations. Additionally, periodic axial metal strip cylinders are inserted into the bore, resulting in improved field uniformity in a phantom with a simultaneous increase in SNR. The numerical analysis for nonquasi-static fields can be computationally intensive, and the numerical error for finite-element simulations is quantified using modified boundary conditions of the system. When the waveguide effects are taken into account, the mode content in the images compares well to full-wave simulations.
|Original language||English (US)|
|Number of pages||11|
|Journal||IEEE Transactions on Microwave Theory and Techniques|
|State||Published - Jul 2017|
Bibliographical noteFunding Information:
This work was supported in part by the National Science Foundation under Collaborative Research Grant ECCS 1307614 at the University of Colorado, Boulder, and in part by the National Institutes of Health under Grant P41 EB015894 and Grant S10 RR029672.
- magnetic resonance imaging (MRI)
- patch antenna