永磁磁共振成像中射频表面线圈的优化设计  

SNR-optimized approach for the design of RF surface coils for permanent MRI systems

作　　者：褚旭[1] 蒋晓华[1] 

机构地区：[1]清华大学电机工程与应用电子技术系,北京100084

出　　处：《清华大学学报（自然科学版）》2005年第3期351-354,共4页Journal of Tsinghua University(Science and Technology)

摘　　要：提出了一种以信噪比为优化目标的射频表面线圈的优化设计方法。在电磁分析中采用无穷大的均匀介质来近似模拟计算人体产生的噪声,以Fourier级数为基函数将线圈所在平面的源电流密度按函数展开,以展开系数为自变量对线圈的信噪比进行优化。利用该方法设计制作了一个表面线圈,在一台0.3T磁共振成像系统上进行了水模和人体的成像实验,结果表明,该线圈在较浅深度上的信噪比超过了正交体线圈,而在所有深度上都超过了以均匀度为优化目标设计出来的蝶形线圈。The signal-to-noise ratios (SNR) of radio-frequency surface coils with a proper field-of-view were optimized using a design approach based on functional methods. The power losses in the sample and the coil were minimized while the sensitivity at a given point of interest was fixed as specified. Continuous current density distributions were derived and the stream function technique was then used to obtain the conductor paths. A prototype surface coil was designed and constructed for a 0.3 T permanent magnetic resonance imaging (MRI) system. Phantom and in vivo images show that the coil generates a higher SNR than a clinical quadrature body coil at relatively superficial depths and that the SNR exceeds that of a traditional butterfly coil at all depths.

关 键 词：核磁共振成像 射频线圈 表面线圈 信噪比 

分 类 号：O482.53[理学—固体物理]