Xie Huidong, Guo Liang, Velo Alexandre, Liu Zhao, Liu Qiong, Guo Xueqi, Zhou Bo, Chen Xiongchao, Tsai Yu-Jung, Miao Tianshun, Xia Menghua, Liu Yi-Hwa, Armstrong Ian S, Wang Ge, Carson Richard E, Sinusas Albert J, Liu Chi
Department of Biomedical Engineering, Yale University, USA.
Department of Biomedical Engineering, Yale University, USA.
Med Image Anal. 2025 Feb;100:103391. doi: 10.1016/j.media.2024.103391. Epub 2024 Nov 20.
Rubidium-82 (Rb) is a radioactive isotope widely used for cardiac PET imaging. Despite numerous benefits of Rb, there are several factors that limits its image quality and quantitative accuracy. First, the short half-life of Rb results in noisy dynamic frames. Low signal-to-noise ratio would result in inaccurate and biased image quantification. Noisy dynamic frames also lead to highly noisy parametric images. The noise levels also vary substantially in different dynamic frames due to radiotracer decay and short half-life. Existing denoising methods are not applicable for this task due to the lack of paired training inputs/labels and inability to generalize across varying noise levels. Second, Rb emits high-energy positrons. Compared with other tracers such as F, Rb travels a longer distance before annihilation, which negatively affect image spatial resolution. Here, the goal of this study is to propose a self-supervised method for simultaneous (1) noise-aware dynamic image denoising and (2) positron range correction for Rb cardiac PET imaging. Tested on a series of PET scans from a cohort of normal volunteers, the proposed method produced images with superior visual quality. To demonstrate the improvement in image quantification, we compared image-derived input functions (IDIFs) with arterial input functions (AIFs) from continuous arterial blood samples. The IDIF derived from the proposed method led to lower AUC differences, decreasing from 11.09% to 7.58% on average, compared to the original dynamic frames. The proposed method also improved the quantification of myocardium blood flow (MBF), as validated against O-water scans, with mean MBF differences decreased from 0.43 to 0.09, compared to the original dynamic frames. We also conducted a generalizability experiment on 37 patient scans obtained from a different country using a different scanner. The presented method enhanced defect contrast and resulted in lower regional MBF in areas with perfusion defects. Lastly, comparison with other related methods is included to show the effectiveness of the proposed method.
铷 - 82（Rb）是一种广泛用于心脏PET成像的放射性同位素。尽管Rb有诸多优点，但仍有几个因素限制了其图像质量和定量准确性。首先，Rb的半衰期短导致动态帧出现噪声。低信噪比会导致图像定量不准确且有偏差。有噪声的动态帧还会导致参数图像噪声很高。由于放射性示踪剂衰变和半衰期短，不同动态帧中的噪声水平也有很大差异。由于缺乏配对的训练输入/标签以及无法在不同噪声水平上进行泛化，现有的去噪方法不适用于此任务。其次，Rb发射高能正电子。与其他示踪剂如F相比，Rb在湮灭前传播的距离更长，这对图像空间分辨率有负面影响。在此，本研究的目标是提出一种自监督方法，用于同时（1）进行噪声感知动态图像去噪和（2）对Rb心脏PET成像进行正电子射程校正。在一组正常志愿者的一系列PET扫描上进行测试，所提出的方法产生了视觉质量更高的图像。为了证明图像定量方面的改进，我们将图像衍生输入函数（IDIF）与来自连续动脉血样的动脉输入函数（AIF）进行了比较。与原始动态帧相比，所提出方法衍生的IDIF导致较低的AUC差异，平均从11.09%降至7.58%。与O - 水扫描验证相比，所提出的方法还改善了心肌血流量（MBF）的定量，与原始动态帧相比，平均MBF差异从0.43降至0.09。我们还对从另一个国家使用不同扫描仪获得的37例患者扫描进行了泛化实验。所提出的方法增强了缺损对比度，并在灌注缺损区域导致较低的局部MBF。最后，与其他相关方法进行比较以显示所提出方法的有效性。
