Department of Radiology, University of Minnesota, Minneapolis, MN, USA.
Magn Reson Med. 2012 Apr;67(4):954-64. doi: 10.1002/mrm.23070. Epub 2011 Nov 18.
Eight- and sixteen-channel transceive stripline/TEM body arrays were compared at 7 T (297 MHz) both in simulation and experiment. Despite previous demonstrations of similar arrays for use in body applications, a quantitative comparison of the two configurations has not been undertaken to date. Results were obtained on a male pelvis for assessing transmit, signal to noise ratio, and parallel imaging performance and to evaluate local power deposition versus transmit B(1) (B(1) (+) ). All measurements and simulations were conducted after performing local B(1) (+) phase shimming in the region of the prostate. Despite the additional challenges of decoupling immediately adjacent coils, the sixteen-channel array demonstrated improved or nearly equivalent performance to the eight-channel array based on the evaluation criteria. Experimentally, transmit performance and signal to noise ratio were 22% higher for the sixteen-channel array while significantly increased reduction factors were achievable in the left-right direction for parallel imaging. Finite difference time domain simulations demonstrated similar results with respect to transmit and parallel imaging performance, however, a higher transmit efficiency advantage of 33% was predicted. Simulations at both 3 and 7 T verified the expected parallel imaging improvements with increasing field strength and showed that, for a specific B(1) (+) shimming strategy used, the sixteen-channel array exhibited lower local and global specific absorption rate for a given B(1) (+) .
在 7T（297MHz）下，对 8 通道和 16 通道收发带状线/TEM 体阵列进行了仿真和实验比较。尽管之前已经展示了类似的阵列可用于体应用，但迄今为止尚未对这两种配置进行定量比较。研究结果是在男性骨盆上获得的，用于评估发射、信噪比和并行成像性能，并评估局部功率沉积与发射 B(1)（B(1) (+)）的关系。所有测量和模拟都是在前列腺区域进行局部 B(1) (+) 相位调谐后进行的。尽管立即解耦相邻线圈具有额外的挑战，但根据评估标准，十六通道阵列显示出比八通道阵列更好或几乎相同的性能。实验中，十六通道阵列的发射性能和信噪比提高了 22%，而并行成像在左右方向上可实现显著增加的缩减因子。有限差分时域仿真在发射和并行成像性能方面也得到了类似的结果，但预测的发射效率优势更高，达到 33%。在 3T 和 7T 下的仿真验证了随着场强的增加并行成像的预期改善，并且表明对于特定的 B(1) (+) 调谐策略，在给定的 B(1) (+) 下，十六通道阵列显示出更低的局部和全局比吸收率。
