Abstract
Numerical modeling and experimental results are presented for a variety of birdcages for high-field MRI microscopy. The data include the first published numerical calculations and experimental measurements of magnetic filling factors of birdcages or other MRI coils. Fast, 3D calculations for shielded coils are demonstrated using the Biot-Savart law along with energy minimization. It is shown that the near-field, higher-order inhomogeneity effects remaining after a first-order, asymmetry correction may easily exceed 20% in situations where it is desirable to maximize filling factor. It is also found that an order-of-magnitude improvement in the accuracy of predicted capacitor values may be achieved by using a more detailed circuit model of the birdcage resonator.
Original language | English |
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Pages (from-to) | 144-154 |
Number of pages | 11 |
Journal | Journal of Magnetic Resonance |
Volume | 138 |
Issue number | 1 |
DOIs | |
State | Published - May 1999 |
Externally published | Yes |
Funding
The authors thank numerous technicians and engineers at (or formerly at) Doty Scientific, especially Xunming Chen, Andy Yang, Eugene Deyneka, Glenn Doty, David McCree, Jiong Shao, Art Boman, and Mark Moore, for their assistance in programming, experiments, calculations, analysis, and prototyping. The authors also thank the referees for a number of helpful comments. This work was supported by Doty Scientific, Inc.
Keywords
- Birdcage
- Coils
- Filling factor
- Inhomogeneity
- Microscopy