Dual-frequency, dual-quadrature, birdcage RF coil design with identical b1 pattern for sodium and proton imaging of the human brain at 1.5 T
✍ Scribed by Gary X. Shen; Fernando E. Boada; Keith R. Thulborn
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 862 KB
- Volume
- 38
- Category
- Article
- ISSN
- 0740-3194
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✦ Synopsis
Rapid quantification of tissue metabolites in vivo by MRS or MRI can be achieved using dual-frequency RF coils with identical B1 field distributions at the observation frequencies of the metabolites and tissue water protons. Tissue sodium is used as an example for optimizing the dual-frequency, dual-quadrature RF coils for such measurements in humans. In the setting of sodium imaging, the challenge of dual-quadrature birdcage configurations is to decouple the sodium and proton channels because the fourth harmonic of the sodium frequency is very close to the proton frequency. A generalizable method for effectively decoupling these two RF frequencies is presented in this paper. The method is demonstrated with the design of an EPI compatible, dual-quadrature, double-tuned, 23Na/1H birdcage coil. The performance of the RF probe is reported at 1.5 Tesla in terms of signal-to-noise ratio, B1 homogeneity and image quality.