Partial FOV Center Imaging (PCI): A Robust X-Space Image Reconstruction for Magnetic Particle Imaging
Partial FOV Center Imaging (PCI): A Robust X-Space Image Reconstruction for Magnetic Particle Imaging
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DOI：
10.1109/tmi.2020.2995410
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发表时间：
2020-11-01
影响因子：
10.6
通讯作者：
Saritas, Emine Ulku
中科院分区：
文献类型：
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作者：
Kurt, Semih;Muslu, Yavuz;Saritas, Emine Ulku
磁粒子成像(MPI)是一种新兴的医学成像手段，它利用超顺磁性氧化铁(SPIO)纳米颗粒对外加磁场的非线性响应来成像其空间分布。在标准的x空间MPI方法中，通过将速度补偿的纳米粒子信号栅格化到自由场(FFP)的瞬时位置来重建图像。然而，由于驾驶场的安全限制，视场(FOV)需要由多个相对较小的局部视场(PFOV)覆盖。然后，从单独处理的pFOV将整个FOV的图像拼接在一起。这些处理步骤可能对非理想信号条件敏感，例如谐波干扰、噪声和松弛效应。在这项工作中，我们提出了一种稳健的x空间重建技术，部分视野中心成像(PCI)，其实质上简化了pFOV处理。PCI首先通过将MPI信号直接映射到pFOV中心位置来形成整个FOV的原始图像。然后，通过用紧凑的核对该原始图像进行去卷积得到相应的MPI图像，其完全已知的形状仅取决于pFOV大小。我们通过大量的模拟以及在我们的内部FFP MPI扫描仪上的成像实验来分析所提出的重建的性能。结果表明，在噪声稳健性和干扰稳健性之间进行了折衷，在对非理想信号条件的稳健性和图像质量方面都优于标准的x空间重建。
Magnetic Particle Imaging (MPI) is an emerging medical imaging modality that images the spatial distribution of superparamagnetic iron oxide (SPIO) nanoparticles using their nonlinear response to applied magnetic fields. In standard x-space approach to MPI, the image is reconstructed by gridding the speed-compensated nanoparticle signal to the instantaneous position of the field free point (FFP). However, due to safety limits on the drive field, the field-of-view (FOV) needs to be covered by multiple relatively small partial field-of-views (pFOVs). The image of the entire FOV is then pieced together from individually processed pFOVs. These processing steps can be sensitive to non-ideal signal conditions such as harmonic interference, noise, and relaxation effects. In this work, we propose a robust x-space reconstruction technique, Partial FOV Center Imaging (PCI), with substantially simplified pFOV processing. PCI first forms a raw image of the entire FOV by mapping MPI signal directly to pFOV center locations. The corresponding MPI image is then obtained by deconvolving this raw image by a compact kernel, whose fully-known shape solely depends on the pFOV size. We analyze the performance of the proposed reconstruction via extensive simulations, as well as imaging experiments on our in-house FFP MPI scanner. The results show that PCI offers a trade-off between noise robustness and interference robustness, outperforming standard x-space reconstruction in terms of both robustness against non-ideal signal conditions and image quality.