Influence and Compensation of Truncation Artifacts in MR-Based Attenuation Correction in PET/MR
Influence and Compensation of Truncation Artifacts in MR-Based Attenuation Correction in PET/MR
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DOI：
10.1109/tmi.2013.2272660
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发表时间：
2013-11-01
影响因子：
10.6
通讯作者：
van den Hoff, J.
中科院分区：
文献类型：
--
作者：
Schramm, G.;Langner, J.;van den Hoff, J.
本文的目的是量化截断伪影在磁共振（MR）的衰减图（MRMap）重建的正电子发射断层扫描（PET）图像体积的影响，并提出一种新的方法，以尽量减少这种影响。研究方法：在Philips Incidity PET/MR中研究的20例患者的PET数据集在应用和不应用两种不同的截断补偿方法（TC 1供应商提供，TC 2新开发）的情况下进行重建。在该患者组中，在MRMap中目视评估截断伪影的程度和截断补偿（TC）的质量。在另外三名患者中，可以将算法TC 2生成的MR图与使用Siemens ECAT HR+扫描仪获得的基于透射的衰减图的真实值进行比较。在适当的感兴趣体积（VOI）中评估截断对病变、其他热结构（膀胱、肾脏、心肌）和手臂中局部SUV的影响。结果如下：对于算法TC 1，16例患者的手臂中显示出截断补偿MR图残留伪影，对于算法TC 2，8例患者的手臂中显示出较小程度的截断补偿MR图残留伪影。与基于透射的衰减图相比，算法TC 2在径向方向上略微高估了截断臂的尺寸0.3 cm。在没有截断补偿的情况下，位于躯干中的VOI显示相对于TC 2获得的结果，平均SUVmax低估小于5.4%。结论：在躯干，标准化摄取值（SUV）低估由于截断伪影在MRMap是相当小的。在武器内部，可能会发生严重的SUV低估。因此，可靠的TC是强制性的，可以通过应用新开发的算法TC 2，迄今为止已经取得了可喜的成果。所提出的方法的实施是简单的，应该很容易适应其他PET/MR系统。
The goal of this article is to quantify the influence of truncation artifacts in the magnetic resonance (MR)-based attenuation map (MRMap) on reconstructed positron emission tomography (PET) image volumes and to propose a new method for minimizing this influence. Methods: PET data sets of 20 patients investigated in a Philips Ingenuity PET/MR were reconstructed with and without applying two different methods for truncation compensation (TC1 vendor-provided, TC2 newly developed). In this patient group, the extent of truncation artifacts and quality of the truncation compensation (TC) was assessed visually in the MRMaps. In three additional patients MRMaps generated by algorithm TC2 could be compared to the ground truth of transmission-based attenuation maps obtained with a Siemens ECAT HR+ scanner. The influence of truncation on regional SUVs in lesions, other hot structures (bladder, kidney, myocardium) and the arms was assessed in suitable volume of interests (VOI). Results: Truncation compensated MRMaps exhibited residual artifacts in the arms in 16 patients for algorithm TC1 and to a lesser extent in eight patients for algorithm TC2. Compared to the transmission-based attenuation maps algorithm TC2 slightly overestimated the size of the truncated arms by 0.3 cm in the radial direction. Without truncation compensation, VOIs located in the trunk showed an average SUVmax underestimation of less than 5.4% relative to the results obtained with TC2. Inside the patients' arms underestimations up to 46.5% were found. Conclusion: In the trunk, standardized uptake values (SUV) underestimations due to truncation artifacts in the MRMap are rather small. Inside the arms, severe SUV under-estimations can occur. Therefore, reliable TC is mandatory and can be achieved by applying the newly developed algorithm TC2 which has yielded promising results so far. Implementation of the proposed method is straightforward and should be easily adaptable to other PET/MR systems.