背景:临床PET扫描仪的有限空间分辨率导致图像模糊,并且不允许精确量化非常薄或小的结构(称为部分体积效应)。在心脏成像中,临床相关问题,例如,为了准确定义瘢痕心肌组织的程度或残余代谢活动,可以受益于部分体积校正(PVC)技术。使用高分辨率解剖信息来改善PET数据集的重建已成功应用于其他解剖区域。然而,出现了一些与在心脏数据集上使用PVC的任何解剖信息有关的问题。心灵的动人本质,加上可能不同时采集的解剖和活动数据集,可能会在PET和解剖图像之间引入差异,这反过来可能会误导病变的量化和检测。在这种情况下,非解剖学(边缘保留)先验可以代表PVC的可行替代方案。在这项工作中,我们调查并比较了在心脏PET数据集的最大后验(MAP)重建过程中应用的不同解剖和非解剖先验的正则效应.本文的重点是心肌(18)F-FDGPET的准确定量和病变检测。
方法:模拟数据集,用XCAT软件获得,用不同的算法重构,并进行定量分析。
结果:这项模拟研究的结果表明,当理想,使用完美匹配的解剖结构。为了使PVC成功,解剖信息必须清楚地区分正常心肌组织和瘢痕心肌组织。如果解剖信息不匹配或丢失,基于解剖的MAP重建的质量降低,影响整体图像质量和病变量化。边缘保留先验产生具有良好噪声特性和活动恢复的重建,具有不依赖外部的优势,额外的解剖扫描。
结论:边缘保留先验的性能是可以接受的,但不如那些在病变和正常组织之间进行区分的良好应用的解剖学先验,在重建图像中的病变的检测和量化。当考虑牛眼图时,所有测试的MAP算法均产生了可比的结果.
BACKGROUND: The limited spatial resolution of the clinical PET scanners results in image blurring and does not allow for accurate quantification of very thin or small structures (known as partial volume effect). In cardiac imaging, clinically relevant questions, e.g. to accurately define the extent or the residual metabolic activity of scarred myocardial tissue, could benefit from partial volume correction (PVC) techniques. The use of high-resolution anatomical information for improved reconstruction of the PET datasets has been successfully applied in other anatomical regions. However, several concerns linked to the use of any kind of anatomical information for PVC on cardiac datasets arise. The moving nature of the heart, coupled with the possibly non-simultaneous acquisition of the anatomical and the activity datasets, is likely to introduce discrepancies between the PET and the anatomical image, that in turn might mislead lesion quantification and detection. Non-anatomical (edge-preserving) priors could represent a viable alternative for PVC in this case. In this work, we investigate and compare the regularizing effect of different anatomical and non-anatomical priors applied during maximum-a-posteriori (MAP) reconstruction of cardiac PET datasets. The focus of this paper is on accurate quantification and lesion detection in myocardial (18)F-FDG PET.
METHODS: Simulated datasets, obtained with the XCAT software, are reconstructed with different algorithms and are quantitatively analysed.
RESULTS: The results of this simulation study show a superiority of the anatomical prior when an ideal, perfectly matching anatomy is used. The anatomical information must clearly differentiate between normal and scarred myocardial tissue for the PVC to be successful. In case of mismatched or missing anatomical information, the quality of the anatomy-based MAP reconstructions decreases, affecting both overall image quality and lesion quantification. The edge-preserving priors produce reconstructions with good noise properties and recovery of activity, with the advantage of not relying on an external, additional scan for anatomy.
CONCLUSIONS: The performance of edge-preserving priors is acceptable but inferior to those of a well-applied anatomical prior that differentiates between lesion and normal tissue, in the detection and quantification of a lesion in the reconstructed images. When considering bull\'s eye plots, all of the tested MAP algorithms produced comparable results.