Parallel RF transmission with eight channels at 3 Tesla
| Autor: | Franz Hebrank, Borjan Gagoski, Franz Schmitt, Vijayanand Alagappan, Ulrich Fontius, Lawrence L. Wald, Kawin Setsompop, Elfar Adalsteinsson |
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| Rok vydání: | 2006 |
| Předmět: |
Physics
Scanner business.industry Phantoms Imaging Radio Waves Reproducibility of Results Signal Processing Computer-Assisted Equipment Design Image Enhancement Magnetic Resonance Imaging Sensitivity and Specificity Pulse (physics) Equipment Failure Analysis Optics Nuclear magnetic resonance Transmission (telecommunications) Electromagnetic coil Excited state Image Interpretation Computer-Assisted Trajectory Waveform Radiology Nuclear Medicine and imaging business Excitation |
| Zdroj: | Magnetic resonance in medicine. 56(5) |
| ISSN: | 0740-3194 |
| Popis: | Spatially selective RF waveforms were designed and demonstrated for parallel excitation with a dedicated eight-coil transmit array on a modified 3T human MRI scanner. Measured excitation profiles of individual coils in the array were used in a low-flip-angle pulse design to achieve desired spatial target profiles with two- (2D) and three-dimensional (3D) k-space excitation with simultaneous transmission of RF on eight channels. The 2D pulse excited a high-resolution spatial pattern in-plane, while the 3D trajectory produced high-quality slice selection with a uniform in-plane excitation despite the highly nonuniform individual spatial profiles of the coil array. The multichannel parallel RF excitation was used to accelerate the 2D excitation by factors of 2–8, and experimental results were in excellent agreement with simulations based on the measured coil maps. Parallel RF transmission may become critical for robust and routine human studies at very high field strengths where B1 inhomogeneity is commonly severe. Magn Reson Med, 2006. © 2006 Wiley-Liss, Inc. |
| Databáze: | OpenAIRE |
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