Department of Radiology, Medical Physics, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany.
Institute for Telecommunications Research, University of South Australia, Mawson Lakes, South Australia, Australia.
Magn Reson Med. 2018 Feb;79(2):1181-1191. doi: 10.1002/mrm.26700. Epub 2017 Apr 25.
Design, implement, integrate, and characterize a customized coil system that allows for generating spatial encoding magnetic fields (SEMs) in a highly-flexible fashion.
A gradient coil with a high number of individual elements was designed. Dimensions of the coil were chosen to mimic a whole-body gradient system, scaled down to a head insert. Mechanical shape and wire layout of each element were optimized to increase the local gradient strength while minimizing eddy current effects and simultaneously considering manufacturing constraints.
Resulting wire layout and mechanical design is presented. A prototype matrix gradient coil with 12 × 7 = 84 elements consisting of two element types was realized and characterized. Measured eddy currents are <1% of the original field. The coil is shown to be capable of creating nonlinear, and linear SEMs. In a DSV of 0.22 m gradient strengths between 24 mT∕m and 78 mT∕m could be realized locally with maximum currents of 150 A. Initial proof-of-concept imaging experiments using linear and nonlinear encoding fields are demonstrated.
A shielded matrix gradient coil setup capable of generating encoding fields in a highly-flexible manner was designed and implemented. The presented setup is expected to serve as a basis for validating novel imaging techniques that rely on nonlinear spatial encoding fields. Magn Reson Med 79:1181-1191, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
设计、实现、集成并表征一种定制的线圈系统，以便以高度灵活的方式产生空间编码磁场（SEMs）。
设计了一个具有大量单个元件的梯度线圈。选择线圈的尺寸以模拟全身梯度系统，缩小到头部插入物。每个元件的机械形状和布线布局都经过优化，以增加局部梯度强度，同时最小化涡流效应，并同时考虑制造限制。
呈现出布线布局和机械设计。实现并表征了一个具有 12×7=84 个元件的原型矩阵梯度线圈，由两种元件类型组成。测量到的涡流小于原始磁场的 1%。该线圈被证明能够产生非线性和线性 SEMs。在 0.22 m 的 DSV 中，可以在局部产生 24 mT/m 至 78 mT/m 之间的梯度强度，最大电流为 150 A。使用线性和非线性编码场进行了初始概念验证成像实验。
设计并实现了一种能够以高度灵活的方式产生编码场的屏蔽矩阵梯度线圈设置。所提出的设置有望成为验证依赖于非线性空间编码场的新型成像技术的基础。磁共振医学 79:1181-1191, 2018。©2017 年国际磁共振学会。
