Non-Equispaced System Matrix Acquisition for Magnetic Particle Imaging Based on Lissajous Node Points
Non-Equispaced System Matrix Acquisition for Magnetic Particle Imaging Based on Lissajous Node Points
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DOI：
10.1109/tmi.2016.2580458
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发表时间：
2016-11-01
影响因子：
10.6
通讯作者：
Buzug, Thorsten M.
中科院分区：
文献类型：
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作者：
Kaethner, Christian;Erb, Wolfgang;Buzug, Thorsten M.
磁粒子成像(MPI)是临床前成像领域的一项新兴技术。粒子信号的采集是沿着覆盖限定视场(FOV)的特定采样轨迹来实现的。在基于系统矩阵(SM)的重建过程中，MPI中常用的捕获路径是李萨如轨迹。这种轨迹的特点是FOV的覆盖不均匀，即中心区域的采样密度低于朝向FOV边缘的区域。传统上，相应的SM获取和随后的重建不反映这种不均匀的覆盖。取而代之的是，它们在等间距的网格上执行。这项工作的目的是引入一种采样网格，通过使用李萨如轨迹的结点来固有地表现上述不均质性。与重建的MPI信号的定制多项式内插配对，可以恢复整个图像。首次将这种与轨迹相关的非等间距网格用于模拟和测量MPI数据的图像重建，结果表明，在保持空间分辨率不变的情况下，可以减少采样位置的数量。
Magnetic Particle Imaging (MPI) is an emerging technology in the field of (pre)clinical imaging. The acquisition of a particle signal is realized along specific sampling trajectories covering a defined field of view (FOV). In a system matrix (SM) based reconstruction procedure, the commonly used acquisition path in MPI is a Lissajous trajectory. Such a trajectory features an inhomogeneous coverage of the FOV, i.e. the center region is sampled less dense than the regions towards the edges of the FOV. Conventionally, the respective SM acquisition and the subsequent reconstruction do not reflect this inhomogeneous coverage. Instead, they are performed on an equispaced grid. The objective of this work is to introduce a sampling grid that inherently features the aforementioned inhomogeneity by using node points of Lissajous trajectories. Paired with a tailored polynomial interpolation of the reconstructed MPI signal, the entire image can be recovered. It is the first time that such a trajectory related non-equispaced grid is used for image reconstruction on simulated and measured MPI data and it is shown that the number of sampling positions can be reduced, while the spatial resolution remains constant.