Optimization of head phased array coil design in magnetic resonance imaging using method of moment its principles and applications

• Main Authors: Lin, Fa-Hsuan, 林發暄
• Other Authors: Chen, Jyh-Horng
• Format: Others
• Language: en_US
• Published: 1996
• Online Access: http://ndltd.ncl.edu.tw/handle/09025167341333010350

碩士 === 國立臺灣大學 === 電機工程研究所 === 84 === Brain research has utilized lots of the most advanced radiological medicine technologies, such as functional magnetic resonance imaging (fMRI), magnetic resonance angiography (MRA), in-vivo magnetic reso- nance spectroscopy(InVivo MRS) and radiosurgery. While these techno- logies are usually implemented with high SNR, high resolution magnetic resonance imaging (MRI) for optimal performance. Nowadays, clinical brain MR images are often acquired via conventional volume coils, such as saddle, Alderman-Grant or birdcage coil. These coils function as RF pulse transmitters as well as RF signal receivers. Due to anatomical size of brain, volume coils require field-of-view (FOV) no less than 25 cm x 25 cm to avoid aliasing artifact. Such a constraint sets the upper bound of spatial resolution of images from volume coils. Although we can get high resolution images by combing volume saturation and small FOV scanning, images are usually with low SNR due to volume coil characteristics. Phased array coil provides an alternative solution to this dilemma. Several surface coils consist a phased array coil with appropriate over- lapping among one another to cancel mutual interaction. Thus each sur- face coil receives different local region images while maintains image characteristics of high signal-to-noise ratio (SNR) of surface coils. These surface coil images can then be combined to generate an image of large FOV comparable to the volume coil images. The goal of this study is to develop a new RF coil phased array. During initial clinical diagnosis, we can utilize this system to have large FOV/low resolution images without neglecting sparsely distributed mul- tiple lesions. Afterward, we can also use this RF coil array to acquire local high resolution high SNR images for further detailed diagnosis and therapy planning.