Several factors may decrease the accuracy of quantitative PET myocardial perfusion imaging (MPI). It is therefore essential to ensure that myocardial blood flow (MBF) values are reproducible and accurate, and to design systematic protocols to achieve this. Until now, no systematic phantom protocols have been available to assess the technical factors affecting measurement accuracy and reproducibility in MPI. We implemented a standard measurement protocol, which applies a flow phantom in order to compare image-derived flow values with respect to a ground truth flow value with [15O]H2O MPI performed on both a Discovery MI (DMI-20, GE Healthcare) and a Biograph Vision 600 (Vision-600, Siemens Healthineers) system. Both systems have automatic [15O]H2O radio water generators (Hidex Oy) individually installed, allowing us to also study the differences occurring due to two different bolus delivery systems. To investigate the technical factors contributing to the modelled flow values, we extracted the [15O]H2O bolus profiles, the flow values from the kinetic modeling (Qin and Qout), and finally calculated their differences between test-retest measurements on both systems. The measurements performed on the DMI-20 system produced Qin and Qout values corresponging to each other as well as to the reference flow value across all test-retest measurements. The repeatability differences on DMI-20 were 2.1% ± 2.6% and 3.3% ± 4.1% for Qin and Qout, respectively. On Vision-600 they were 10% ± 8.4% and 11% ± 10% for Qin and Qout, respectively. The measurements performed on the Vision-600 system showed more variation between Qin and Qout values across test-retest measurements and exceeded 15% difference in 7/24 of the measurements. A preliminary protocol for measuring the accuracy and reproducibility of flow values in [15O]H2O MPI between digital PET/CT systems was assessed. The test-retest reproducibility falls below 15% in majority of the measurements conducted between two individual injector systems and two digital PET/CT systems. This study highlights the importance of implementing a standardized bolus injection and delivery protocol and importance of assessing technical factors affecting flow value reproducibility, which should be carefully investigated in a multi-center setting.

中文翻译：

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使用流动体模测量 [15O]H2O 心肌灌注成像中数字 PET/CT 系统流量值的再现性和准确性的初步方案


有几个因素可能会降低定量 PET 心肌灌注成像 (MPI) 的准确性。因此，必须确保心肌血流 (MBF) 值的可重复性和准确性，并设计系统方案来实现这一目标。到目前为止，还没有系统的模型协议可用于评估影响 MPI 测量精度和再现性的技术因素。我们实施了一个标准测量协议，该协议应用流模型，以便将图像导出的流量值与地面真实流量值进行比较，并在 Discovery MI（DMI-20，GE Healthcare）和Biograph Vision 600（Vision-600，西门子 Healthineers）系统。两个系统都单独安装了自动 [15O]H2O 无线电水发生器 (Hidex Oy)，使我们能够研究由于两种不同的推注输送系统而产生的差异。为了研究影响建模流量值的技术因素，我们提取了 [15O]H2O 推注曲线、动力学模型中的流量值（Qin 和 Qout），并最终计算了两个系统上的重测测量值之间的差异。在 DMI-20 系统上执行的测量产生相互对应的 Qin 和 Qout 值，以及所有重测测量中的参考流量值。 Qin 和 Qout 在 DMI-20 上的重复性差异分别为 2.1% ± 2.6% 和 3.3% ± 4.1%。在 Vision-600 上，Qin 和 Qout 分别为 10% ± 8.4% 和 11% ± 10%。在 Vision-600 系统上执行的测量显示，在重测测量中，Qin 和 Qout 值之间存在更多差异，并且 7/24 的测量中差异超过 15%。 评估了测量数字 PET/CT 系统之间 [15O]H2O MPI 中流量值的准确性和再现性的初步方案。在两个独立注射器系统和两个数字 PET/CT 系统之间进行的大多数测量中，重测重现性均低于 15%。这项研究强调了实施标准化推注和输送方案的重要性以及评估影响流量值再现性的技术因素的重要性，应在多中心环境中仔细研究。