Effects of end-ring/shield configuration on homogeneity and signal-to-noise ratio in a birdcage-type coil loaded with a human head
Effects of end-ring/shield configuration on homogeneity and signal-to-noise ratio in a birdcage-type coil loaded with a human head
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DOI：
10.1002/mrm.10683
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发表时间：
2004-01-01
影响因子：
3.3
通讯作者：
Smith, MB
中科院分区：
文献类型：
--
作者：
Liu, WZ;Collins, CM;Smith, MB
我们模拟了四种不同的端环/屏蔽配置的鸟笼线圈，以研究其在64 MHz和125 MHz的磁场均匀性和信噪比（SNR）的影响。这些配置被定义为：1）常规的：常规的圆柱形屏蔽件; 2）环绕屏蔽件：具有环形延伸部以紧密地屏蔽端环的屏蔽件; 3）固体连接：具有连接到横档的环形延伸部的屏蔽件;以及4）细线连接：具有连接到横档的细线的屏蔽件。在两个频率下，具有常规端环/屏蔽配置的线圈在线圈为空时产生最均匀的RF磁场（B-1），但在线圈装载有人头部时产生最不均匀的B-1场。周围的屏蔽配置导致在两个频率下加载有人头的线圈中最均匀的B-1和最高的SNR，紧接着是固体连接配置。(C)2003 Wiley-Liss，Inc.
We modeled four different end-ring/shield configurations of a birdcage coil to examine their effects on field homogeneity and signal-to-noise ratio (SNR) at 64 MHz and 125 MHz. The configurations are defined as: 1) conventional: a conventional cylindrical shield; 2) surrounding shield: a shield with annular extensions to closely shield the end rings; 3) solid connection: a shield with annular extensions connected to the rungs; and 4) thin wire connection: a shield with thin wires connected to the rungs. At both frequencies, the coil with conventional end-ring/shield configuration produces the most homogeneous RF magnetic (B-1) field when the coil is empty, but produces the least homogeneous B-1 field when the coil is loaded with a human head. The surrounding shield configuration results in the most homogeneous B-1 and highest SNR in the coil loaded with the human head at both frequencies, followed closely by the solid connection configuration. (C) 2003 Wiley-Liss, Inc.