Department of Nuclear Medicine, University Hospital Würzburg, Würzburg, Germany.
Comprehensive Heart Failure Center University Hospital Würzburg, Würzburg, Germany.
Mol Imaging. 2022 Feb 23;2022:7056983. doi: 10.1155/2022/7056983. eCollection 2022.
In patients with prostate cancer (PC) receiving prostate-specific membrane antigen- (PSMA-) targeted radioligand therapy (RLT), higher baseline standardized uptake values (SUVs) are linked to improved outcome. Thus, readers deciding on RLT must have certainty on the repeatability of PSMA uptake metrics. As such, we aimed to evaluate the test-retest repeatability of lesion uptake in a large cohort of patients imaged with F-DCFPyL.
In this prospective, IRB-approved trial (NCT03793543), 21 patients with history of histologically proven PC underwent two F-DCFPyL PET/CTs within 7 days (mean 3.7, range 1 to 7 days). Lesions in the bone, lymph nodes (LN), and other organs were manually segmented on both scans, and uptake parameters were assessed (maximum (SUV) and mean (SUV) SUVs), PSMA-tumor volume (PSMA-TV), and total lesion PSMA (TL-PSMA, defined as PSMA - TV × SUV)). Repeatability was determined using Pearson's correlations, within-subject coefficient of variation (wCOV), and Bland-Altman analysis.
In total, 230 pairs of lesions (177 bone, 38 LN, and 15 other) were delineated, demonstrating a wide range of SUV (1.5-80.5) and SUV (1.4-24.8). Including all sites of suspected disease, SUVs had a strong interscan correlation ( ≥ 0.99), with high repeatability for SUV and SUV (wCOV, 7.3% and 12.1%, respectively). High SUVs showed significantly improved wCOV relative to lower SUVs ( < 0.0001), indicating that high SUVs are more repeatable, relative to the magnitude of the underlying SUV. Repeatability for PSMA-TV and TL-PSMA, however, was low (wCOV ≥ 23.5%). Across all metrics for LN and bone lesions, interscan correlation was again strong ( ≥ 0.98). Moreover, LN-based SUV also achieved the best wCOV (3.8%), which was significantly reduced when compared to osseous lesions (7.8%, < 0.0001). This was also noted for SUV (wCOV, LN 8.8% vs. bone 12.0%, < 0.03). On a compartment-based level, wCOVs for volumetric features were ≥22.8%, demonstrating no significant differences between LN and bone lesions (PSMA-TV, =0.63; TL-PSMA, =0.9). Findings on an entire tumor burden level were also corroborated in a hottest lesion analysis investigating the SUV of the most intense lesion per patient ( , 0.99; wCOV, 11.2%).
In this prospective test-retest setting, SUV parameters demonstrated high repeatability, in particular in LNs, while volumetric parameters demonstrated low repeatability. Further, the large number of lesions and wide distribution of SUVs included in this analysis allowed for the demonstration of a dependence of repeatability on SUV, with higher SUVs having more robust repeatability.
在接受前列腺特异性膜抗原-（PSMA-）靶向放射性配体治疗（RLT）的前列腺癌（PC）患者中，较高的基线标准化摄取值（SUVs）与改善的结果相关。因此，决定进行 RLT 的读者必须对 PSMA 摄取指标的可重复性有把握。为此，我们旨在通过 F-DCFPyL 成像的大患者队列评估病变摄取的测试-再测试重复性。
在这项前瞻性、IRB 批准的试验（NCT03793543）中，21 例有组织学证实的 PC 病史的患者在 7 天内接受了两次 F-DCFPyL PET/CT（平均 3.7，范围 1 至 7 天）。在两次扫描上手动对骨、淋巴结（LN）和其他器官的病变进行分段，并评估摄取参数（最大（SUV）和平均（SUV）SUVs）、PSMA 肿瘤体积（PSMA-TV）和总病变 PSMA（TL-PSMA，定义为 PSMA-TV×SUV））。使用 Pearson 相关性、受试者内变异系数（wCOV）和 Bland-Altman 分析来确定重复性。
总共描绘了 230 对病变（177 个骨、38 个 LN 和 15 个其他），显示出广泛的 SUV（1.5-80.5）和 SUV（1.4-24.8）范围。包括所有可疑疾病部位，SUV 具有很强的扫描间相关性（≥0.99），SUV 和 SUV 的重复性很高（wCOV，分别为 7.3%和 12.1%）。高 SUV 与低 SUV 相比，显著改善了 wCOV（<0.0001），表明高 SUV 的重复性相对 SUV 的大小更好。然而，PSMA-TV 和 TL-PSMA 的重复性较低（wCOV≥23.5%）。对于所有 LN 和骨病变的指标，扫描间相关性再次很强（≥0.98）。此外，基于 LN 的 SUV 也达到了最佳的 wCOV（3.8%），与骨病变（7.8%，<0.0001）相比明显降低。这在 SUV 上也得到了证实（wCOV，LN 8.8%比骨 12.0%，<0.03）。在基于隔室的水平上，容积特征的 wCOV 为≥22.8%，LN 和骨病变之间无显著差异（PSMA-TV，=0.63；TL-PSMA，=0.9）。在对每位患者最强烈病变的 SUV 进行最热病变分析的整个肿瘤负担水平上也得到了证实（，0.99；wCOV，11.2%）。
在这项前瞻性的测试-再测试设置中，SUV 参数表现出很高的重复性，特别是在 LN 中，而体积参数则表现出较低的重复性。此外，本分析中包含的大量病变和广泛的 SUV 分布使我们能够证明重复性与 SUV 有关，SUV 越高，重复性越好。
