Abstract:
:A general analytical framework is presented for the design of birdcage radiofrequency resonators on cylindrical formers having arbitrary cross-sectional shape. The primary objective of such shapes would be to improve the sensitivity of the NMR experiment to noncircular regions of the human anatomy while maintaining field homogeneity and quadrature polarization comparable to those of standard circular birdcage coils. The shape of the corresponding radiofrequency screen, which is required to decouple the coil from the rest of the NMR system and which is key to the performance, is also provided by this methodology. The theory was tested by constructing a 3-T, quadrature, proton coil on a shape conforming to the anthropomorphic mean of the human head, namely, the oval of Cassini. Both bench tests (Q) and in vivo spectral and imaging comparisons of the Cassinian coil with an equivalently dimensioned and constructed circular birdcage coil, respectively, predicted and demonstrated in vivo an improvement in SNR of approximately 24% over the circular section coil. The experimental RF field homogeneity and quadrature performance were comparable for both coil geometries, with the circular coil being marginally superior.
journal_name
Magn Reson Medjournal_title
Magnetic resonance in medicineauthors
De Zanche N,Yahya A,Vermeulen FE,Allen PSdoi
10.1002/mrm.20317subject
Has Abstractpub_date
2005-01-01 00:00:00pages
201-11issue
1eissn
0740-3194issn
1522-2594journal_volume
53pub_type
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