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Parallel traveling‐wave MRI: A feasibility study
Author(s) -
Pang Yong,
Vigneron Daniel B.,
Zhang Xiaoliang
Publication year - 2012
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.23073
Subject(s) - decoupling (probability) , sensitivity (control systems) , acoustics , microstrip , patch antenna , orientation (vector space) , antenna (radio) , microstrip antenna , antenna array , computer science , physics , optics , electronic engineering , telecommunications , engineering , mathematics , geometry , control engineering
Abstract Traveling‐wave magnetic resonance imaging utilizes far fields of a single‐piece patch antenna in the magnet bore to generate radio frequency fields for imaging large‐size samples, such as the human body. In this work, the feasibility of applying the “traveling‐wave” technique to parallel imaging is studied using microstrip patch antenna arrays with both the numerical analysis and experimental tests. A specific patch array model is built and each array element is a microstrip patch antenna. Bench tests show that decoupling between two adjacent elements is better than ‐26‐dB while matching of each element reaches ‐36‐dB, demonstrating excellent isolation performance and impedance match capability. The sensitivity patterns are simulated and g‐factors are calculated for both unloaded and loaded cases. The results on B 1 ‐sensitivity patterns and g‐factors demonstrate the feasibility of the traveling‐wave parallel imaging. Simulations also suggest that different array configuration such as patch shape, position and orientation leads to different sensitivity patterns and g‐factor maps, which provides a way to manipulate B 1 fields and improve the parallel imaging performance. The proposed method is also validated by using 7T MR imaging experiments. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.