Active control of the spatial MRI phase distribution with optimal control theory
Active control of the spatial MRI phase distribution with optimal control theory
复制标题
DOI：
10.1016/j.jmr.2017.05.008
复制
发表时间：
2017-08-01
影响因子：
2.2
通讯作者：
Koon, Kevin Tse Ve
中科院分区：
文献类型：
--
作者：
Lefebvre, Pauline M.;Van Reeth, Eric;Koon, Kevin Tse Ve
本文研究了使用最优控制（OC）理论设计射频（RF）脉冲，主动控制MRI磁化相位的空间分布。通过庞特里亚金最大值原理的应用产生的RF脉冲和优化，使所得的横向磁化再现各种非平凡和空间相位图案。定义了两种不同的相位模式，并在4.7 T小动物MR扫描仪上用ODIN MRI模拟器和琼脂凝胶体模进行了数值测试和实验测试。在模拟和实验中获得的相位图像都与定义的相位图案一致。相位控制与OC设计的脉冲的实际应用也被提出，与RF脉冲的产生适用于磁共振弹性成像实验。这项研究证明了使用OC设计的RF脉冲来编码磁化阶段信息的可能性，并且可以在使用相位图像的MRI序列中应用。(C)2017爱思唯尔公司All rights reserved.
This paper investigates the use of Optimal Control (OC) theory to design Radio-Frequency (RF) pulses that actively control the spatial distribution of the MRI magnetization phase. The RF pulses are generated through the application of the Pontryagin Maximum Principle and optimized so that the resulting transverse magnetization reproduces various non-trivial and spatial phase patterns. Two different phase patterns are defined and the resulting optimal pulses are tested both numerically with the ODIN MRI simulator and experimentally with an agar gel phantom on a 4.7 T small-animal MR scanner. Phase images obtained in simulations and experiments are both consistent with the defined phase patterns. A practical application of phase control with OC-designed pulses is also presented, with the generation of RF pulses adapted for a Magnetic Resonance Elastography experiment. This study demonstrates the possibility to use OC-designed RF pulses to encode information in the magnetization phase and could have applications in MRI sequences using phase images. (C) 2017 Elsevier Inc. All rights reserved.