Chen Xiaojun, Jiang Zhenqi, Han Xiao, Wang Xiaolin, Tang Xiaoying
School of Life Science, Beijing Institute of Technology, Beijing 100081, China.
Diagnostics (Basel). 2021 Apr 26;11(5):773. doi: 10.3390/diagnostics11050773.
Magnetic particle imaging (MPI) is a novel non-invasive molecular imaging technology that images the distribution of superparamagnetic iron oxide nanoparticles (SPIONs). It is not affected by imaging depth, with high sensitivity, high resolution, and no radiation. The MPI reconstruction with high precision and high quality is of enormous practical importance, and many studies have been conducted to improve the reconstruction accuracy and quality. MPI reconstruction based on the system matrix (SM) is an important part of MPI reconstruction. In this review, the principle of MPI, current construction methods of SM and the theory of SM-based MPI are discussed. For SM-based approaches, MPI reconstruction mainly has the following problems: the reconstruction problem is an inverse and ill-posed problem, the complex background signals seriously affect the reconstruction results, the field of view cannot cover the entire object, and the available 3D datasets are of relatively large volume. In this review, we compared and grouped different studies on the above issues, including SM-based MPI reconstruction based on the state-of-the-art Tikhonov regularization, SM-based MPI reconstruction based on the improved methods, SM-based MPI reconstruction methods to subtract the background signal, SM-based MPI reconstruction approaches to expand the spatial coverage, and matrix transformations to accelerate SM-based MPI reconstruction. In addition, the current phantoms and performance indicators used for SM-based reconstruction are listed. Finally, certain research suggestions for MPI reconstruction are proposed, expecting that this review will provide a certain reference for researchers in MPI reconstruction and will promote the future applications of MPI in clinical medicine.
磁粒子成像（MPI）是一种新型的非侵入性分子成像技术，用于对超顺磁性氧化铁纳米颗粒（SPIONs）的分布进行成像。它不受成像深度的影响，具有高灵敏度、高分辨率且无辐射。高精度和高质量的MPI重建具有巨大的实际意义，并且已经开展了许多研究来提高重建的准确性和质量。基于系统矩阵（SM）的MPI重建是MPI重建的重要组成部分。在本综述中，将讨论MPI的原理、SM的当前构建方法以及基于SM的MPI理论。对于基于SM的方法，MPI重建主要存在以下问题：重建问题是一个逆问题且不适定，复杂的背景信号严重影响重建结果，视野无法覆盖整个物体，并且可用的3D数据集体积相对较大。在本综述中，我们对上述问题的不同研究进行了比较和归类，包括基于最先进的蒂霍诺夫正则化的基于SM的MPI重建、基于改进方法的基于SM的MPI重建、减去背景信号的基于SM的MPI重建方法、扩大空间覆盖范围的基于SM的MPI重建方法以及加速基于SM的MPI重建的矩阵变换。此外，还列出了当前用于基于SM重建的体模和性能指标。最后，对MPI重建提出了一定的研究建议，期望本综述能为MPI重建领域的研究人员提供一定的参考，并推动MPI在临床医学中的未来应用。
