Department of Medical Physics, University of Wisconsin - Madison, 1111 Highland Ave Room 1005, Madison, WI 53707, United States of America.
Department of Radiology, University of Wisconsin - Madison, Madison, WI, United States of America.
Phys Med Biol. 2020 Dec 7;65(22):225003. doi: 10.1088/1361-6560/abb6bb.
Patients with metastatic melanoma often receive F-FDG PET/CT scans on different scanners throughout their monitoring period. In this study, we quantified the impact of scanner harmonization on longitudinal changes in PET standardized uptake values using various harmonization and normalization methods, including an anthropomorphic PET phantom. Twenty metastatic melanoma patients received at least two FDG PET/CT scans, each on two different scanners with an average of 4 months (range: 2-8) between. Scans from a General Electric (GE) Discovery 710 PET CT were harmonized to the GE Discovery VCT using image reconstruction settings matching recovery coefficients in an anthropomorphic phantom with bone equivalent inserts and wall-less synthetic lesions. In patient images, SUV was measured for each melanoma lesion and time-point. Lesions were classified as progressing, stable, or responding based on pre-defined threshold of ±30% change in SUV. For comparison, harmonization was also performed using simpler methods, including harmonization using a NEMA phantom, post-reconstruction filtering, reference region normalization of SUV, and use of SUV instead of SUV In the 20 patients, 90 lesions across two time-points were available for treatment response assessment. Treatment response classification changed in 47% (42/90) of cases after harmonization with anthropomorphic phantom. Before harmonization, 37% (33/90) of the lesions were classified as stable (changing less than 30% between two time-points), while the fraction of stable lesions increased to 58% (52/90) after harmonization. Harmonization with the NEMA phantom agreed with harmonization with the anthropomorphic phantom in 91% (82/90) of cases. Post-reconstruction filtering agreed with anthropomorphic phantom-based harmonization in 83% (75/90) cases. The utilization of reference regions for normalization or SUV was unable to correct for changes as identified by the anthropomorphic phantom-based harmonization. Overall, PET scanner harmonization has a major impact on individual lesion treatment response classification in metastatic melanoma patients. Harmonization using the NEMA phantom yielded similar results to harmonization using anthropomorphic phantom, while the only acceptable post-reconstruction technique was post-reconstruction filtering. Phantom-based harmonization is therefore strongly recommended when comparing lesion uptake across time-points when the images have been acquired on different PET scanners.
患有转移性黑色素瘤的患者在监测期间通常会在不同的扫描仪上接受 F-FDG PET/CT 扫描。在这项研究中，我们使用各种调和和归一化方法，包括拟人 PET 体模，量化了扫描仪调和对 PET 标准化摄取值纵向变化的影响。二十名转移性黑色素瘤患者至少接受了两次 FDG PET/CT 扫描，每次扫描均在两台不同的扫描仪上进行，两次扫描之间的平均时间为 4 个月（范围：2-8）。使用具有骨等效插件和无壁合成病变的拟人体模中的恢复系数匹配的图像重建设置，将通用电气（GE）Discovery 710 PET CT 的扫描调和到通用电气 Discovery VCT。在患者图像中，为每个黑色素瘤病变和时间点测量 SUV。根据 SUV 变化的预定义阈值（±30%），将病变分类为进展、稳定或有反应。为了比较，还使用了更简单的方法进行调和，包括使用 NEMA 体模进行调和、后重建滤波、SUV 的参考区域归一化以及使用 SUV 代替 SUV。在 20 名患者中，有 90 个病变在两个时间点可用于治疗反应评估。在使用拟人体模进行调和后，47%（42/90）的病例的治疗反应分类发生了变化。在调和之前，37%（33/90）的病变被归类为稳定（两个时间点之间变化小于 30%），而调和后稳定病变的比例增加到 58%（52/90）。使用 NEMA 体模进行调和与使用拟人体模进行调和的结果在 91%（82/90）的病例中是一致的。使用拟人体模进行调和与后重建滤波的结果在 83%（75/90）的病例中是一致的。参考区域用于归一化或 SUV 的利用无法纠正拟人体模调和所确定的变化。总体而言，PET 扫描仪调和对转移性黑色素瘤患者的个体病变治疗反应分类有重大影响。使用 NEMA 体模进行调和产生的结果与使用拟人体模进行调和相似，而唯一可接受的后重建技术是后重建滤波。因此，当在不同的 PET 扫描仪上采集图像时，强烈建议在比较时间点上的病变摄取时使用基于体模的调和。
