Maximum-Likelihood Joint Image Reconstruction/Motion Estimation in Attenuation-Corrected Respiratory Gated PET/CT Using a Single Attenuation Map
Maximum-Likelihood Joint Image Reconstruction/Motion Estimation in Attenuation-Corrected Respiratory Gated PET/CT Using a Single Attenuation Map
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DOI：
10.1109/tmi.2015.2464156
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发表时间：
2016-01-01
影响因子：
10.6
通讯作者：
Thielemans, Kris
中科院分区：
文献类型：
--
作者：
Bousse, Alexandre;Bertolli, Ottavia;Thielemans, Kris
这项工作为正电子发射断层扫描（PET）联合图像重建/运动估计（JRM）提供了一个深入的见解，通过最大化似然，其中概率模型考虑了扭曲的衰减。我们的分析表明，对于任何衰减图（mu-map），无论其与PET门是否对齐，最大似然（ML） JRM都返回相同的重构门，这是给定mu-map的变形。我们据此推导了一种联合优化算法，并将其应用于模拟和患者门控的PET数据。我们首先在基于XCAT幻影的呼吸门控PET/CT数据模拟中评估了所提出的算法。我们的研究结果表明，与使用哪种mu-map作为JRM的输入无关：(i)扭曲的mu-map对应于门控mu-map， （ii） JRM在热病变量化方面优于传统的配准后重建和巩固（PRRC）， （iii）重建的门控PET图像与使用门控mu-map获得的图像相似。这表明可以使用屏住呼吸的mu-map。然后，我们将JRM应用于由屏息高分辨率CT （HRCT）获得的mu-map的患者数据，并将结果与PRRC进行比较，其中每个重建的PET图像都通过相应的电影CT门控mu-map获得。结果表明，屏息HRCT的JRM重建效果与cine-CT的PRRC重建效果相近。这为实现运动校正呼吸门控PET/CT提供了一种实用的低剂量解决方案。
This work provides an insight into positron emission tomography (PET) joint image reconstruction/motion estimation (JRM) by maximization of the likelihood, where the probabilistic model accounts for warped attenuation. Our analysis shows that maximum-likelihood (ML) JRM returns the same reconstructed gates for any attenuation map (mu-map) that is a deformation of a given mu-map, regardless of its alignment with the PET gates. We derived a joint optimization algorithm accordingly, and applied it to simulated and patient gated PET data. We first evaluated the proposed algorithm on simulations of respiratory gated PET/CT data based on the XCAT phantom. Our results show that independently of which mu-map is used as input to JRM: (i) the warped mu-maps correspond to the gated mu-maps, (ii) JRM outperforms the traditional post-registration reconstruction and consolidation (PRRC) for hot lesion quantification and (iii) reconstructed gated PET images are similar to those obtained with gated mu-maps. This suggests that a breath-held mu-map can be used. We then applied JRM on patient data with a mu-map derived from a breath-held high resolution CT (HRCT), and compared the results with PRRC, where each reconstructed PET image was obtained with a corresponding cine-CT gated mu-map. Results show that JRM with breath-held HRCT achieves similar reconstruction to that using PRRC with cine-CT. This suggests a practical low-dose solution for implementation of motion-corrected respiratory gated PET/CT.