Jia Feng, Littin Sebastian, Layton Kelvin J, Kroboth Stefan, Yu Huijun, Zaitsev Maxim
Dept. of Radiology, Medical Physics, Medical Center University of Freiburg, Faculty of Medicine, University of Freiburg, Breisacher Str. 60a, 79106 Freiburg, Germany.
Dept. of Radiology, Medical Physics, Medical Center University of Freiburg, Faculty of Medicine, University of Freiburg, Breisacher Str. 60a, 79106 Freiburg, Germany.
J Magn Reson. 2017 Aug;281:217-228. doi: 10.1016/j.jmr.2017.06.006. Epub 2017 Jun 9.
The increasing interest in spatial encoding with non-linear magnetic fields has intensified the need for coils that generates such fields. Matrix coils consisting of multiple coil elements appear to offer a high flexibility in generating customized encoding fields and are particularly promising for localized high resolution imaging applications. However, coil elements of existing matrix coils were primarily designed and constructed for better shimming and therefore are not expected to achieve an optimal performance for local spatial encoding. Moreover, eddy current properties of such coil elements were not fully explored. In this work, an optimization problem is formulated based on the requirement of local non-linear encoding and eddy current reduction that results in novel designs of coil elements for an actively-shielded matrix gradient coil. Two metrics are proposed to assess the performance of different coil element designs. The results are analyzed to reveal new insights into coil element design.
对利用非线性磁场进行空间编码的兴趣与日俱增，这加大了对能产生此类磁场的线圈的需求。由多个线圈元件组成的矩阵线圈在生成定制编码场方面似乎具有很高的灵活性，对于局部高分辨率成像应用尤其具有前景。然而，现有矩阵线圈的线圈元件主要是为了更好地匀场而设计和构建的，因此预计无法在局部空间编码方面实现最佳性能。此外，此类线圈元件的涡流特性尚未得到充分研究。在这项工作中，基于局部非线性编码和减少涡流的要求提出了一个优化问题，从而为有源屏蔽矩阵梯度线圈设计出新型线圈元件。提出了两个指标来评估不同线圈元件设计的性能。对结果进行分析，以揭示线圈元件设计的新见解。
