Image uniformity improvement for birdcage-like volume coils at 400 MHz using multichannel excitations
✍ Scribed by Victor Taracila; Labros S. Petropoulos; Timothy P. Eagan; Robert W. Brown
- Publisher
- John Wiley and Sons
- Year
- 2006
- Tongue
- English
- Weight
- 328 KB
- Volume
- 29B
- Category
- Article
- ISSN
- 1552-5031
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✦ Synopsis
We present a new method to deal with MRI non-uniformities caused by electromagnetic wave interference patterns at 300 -400 MHz in lossy dielectrics. The non-uniformities are also known as "dielectric resonance" effects, yielding bright and dark spots at higher frequencies. The proposed method consists of applying a series of multiple cos(n) (n ϭ 1, . . .) circular current distributions on the birdcage legs in independent MRI experiments. The signals obtained during each experiment are then coalesced into a uniform image using appropriate weighting factors. The level of uniformity is improved by the application of additional cos(n)-birdcage-like channels.