PET Reconstruction With an Anatomical MRI Prior Using Parallel Level Sets
PET Reconstruction With an Anatomical MRI Prior Using Parallel Level Sets
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DOI：
10.1109/tmi.2016.2549601
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发表时间：
2016-09-01
影响因子：
10.6
通讯作者：
Arridge, Simon R.
中科院分区：
文献类型：
--
作者：
Ehrhardt, Matthias J.;Markiewicz, Pawel;Arridge, Simon R.
正电子发射断层扫描 (PET) 和磁共振成像 (MRI) 的结合提供了独特的可能性。在本文中，我们的目标是利用 MRI 的高空间分辨率来增强同时采集的 PET 数据的重建。我们提出了一种新的先验，将结构辅助信息合并到最大后验重建中。新的先验结合了先前针对同一问题提出的先验的优点：它在指导从辅助信息可用的边缘进行重建方面非常有效，并且在没有结构信息可用时，在退化情况下局部减少到保留边缘的总变化。此外，该先验是无分割的、凸的，并且不对 PET 和 MRI 图像的边缘方向的相关性做出先验假设。我们展示了模拟大脑模型的结果以及由西门子 Biograph mMR 获取的硬件模型和临床扫描的真实数据的结果。模拟结果表明，与其他几个先验相比，新先验在增强共同解剖边界和保留独特特征之间具有更好的权衡。此外，它具有更好的平均绝对偏差与平均标准偏差权衡，并产生具有优异的相对 l(2) 误差和结构相似指数的重建。这些发现得到了硬件模型和临床患者的真实数据结果的支持，证实了新的先验能够促进明确的解剖学边界。
The combination of positron emission tomography (PET) and magnetic resonance imaging (MRI) offers unique possibilities. In this paper we aim to exploit the high spatial resolution of MRI to enhance the reconstruction of simultaneously acquired PET data. We propose a new prior to incorporate structural side information into a maximum a posteriori reconstruction. The new prior combines the strengths of previously proposed priors for the same problem: it is very efficient in guiding the reconstruction at edges available from the side information and it reduces locally to edge-preserving total variation in the degenerate case when no structural information is available. In addition, this prior is segmentation-free, convex and no a priori assumptions are made on the correlation of edge directions of the PET and MRI images. We present results for a simulated brain phantom and for real data acquired by the Siemens Biograph mMR for a hardware phantom and a clinical scan. The results from simulations show that the new prior has a better trade-off between enhancing common anatomical boundaries and preserving unique features than several other priors. Moreover, it has a better mean absolute bias-to-mean standard deviation trade-off and yields reconstructions with superior relative l(2)-error and structural similarity index. These findings are underpinned by the real data results from a hardware phantom and a clinical patient confirming that the new prior is capable of promoting well-defined anatomical boundaries.