Department of Radiology, Washington University School of Medicine, 510 S. Kingshighway Blvd, Campus Box 8131, St. Louis, MO, 63110, USA.
Siemens Medical Solutions USA, Inc., 810 Innovation Drive, Knoxville, TN, 37932, USA.
Mol Imaging Biol. 2024 Apr;26(2):284-293. doi: 10.1007/s11307-024-01909-x. Epub 2024 Mar 11.
We aimed to determine the test-retest repeatability of quantitative metrics based on the Patlak slope (PS) versus the standardized uptake value (SUV) among lesions and normal organs on oncologic [F]FDG-PET/CT.
This prospective, single-center study enrolled adults undergoing standard-of-care oncologic [F]FDG-PET/CTs. Early (35-50 min post-injection) and late (75-90 min post-injection) SUV and PS images were reconstructed from dynamic whole-body PET data. Repeat imaging occurred within 7 days. Relevant quantitative metrics were extracted from lesions and normal organs. Repeatability was assessed via mean test-retest percent changes [T-RT %Δ], within-subject coefficients of variation (wCVs), and intra-class correlation coefficients (ICCs).
Nine subjects (mean age, 61.7 ± 6.2 years; 6 females) completed the test-retest protocol. Four subjects collectively had 17 [F]FDG-avid lesions. Lesion wCVs were higher (i.e., worse repeatability) for PS-early-max (16.2%) and PS-early-peak (15.6%) than for SUV-early-max (8.9%) and SUV-early-peak (8.1%), with similar early metric ICCs (0.95-0.98). Lesion wCVs were similar for PS-late-max (8.5%) and PS-late-peak (6.4%) relative to SUV-late-max (9.7%) and SUV-late-peak (7.2%), with similar late metric ICCs (0.93-0.98). There was a significant bias toward higher retest SUV and PS values in the lesion analysis (T-RT %Δ [95% CI]: SUV-late-max, 10.0% [2.6%, 17.0%]; PS-late-max, 20.4% [14.3%, 26.4%]) but not in the normal organ analysis.
Among [F]FDG-avid lesions, the repeatability of PS-based metrics is similar to equivalent SUV-based metrics at late post-injection time points, indicating that PS-based metrics may be suitable for tracking response to oncologic therapies. However, further validation is required in light of our study's limitations, including small sample size and bias toward higher retest values for some metrics.
我们旨在确定基于 Patlak 斜率（PS）与肿瘤[F]FDG-PET/CT 中标准化摄取值（SUV）的定量指标在病变和正常器官中的测试-重测可重复性。
这项前瞻性、单中心研究纳入了接受标准护理肿瘤[F]FDG-PET/CT 的成年人。从动态全身 PET 数据中重建早期（注射后 35-50 分钟）和晚期（注射后 75-90 分钟）SUV 和 PS 图像。在 7 天内进行重复成像。从病变和正常器官中提取相关定量指标。通过平均测试-重测百分比变化[T-RT%Δ]、个体内变异系数（wCV）和组内相关系数（ICC）评估可重复性。
9 名受试者（平均年龄 61.7±6.2 岁；6 名女性）完成了测试-重测方案。4 名受试者共有 17 个[F]FDG 摄取病变。PS-early-max（16.2%）和 PS-early-peak（15.6%）的病变 wCV 高于 SUV-early-max（8.9%）和 SUV-early-peak（8.1%），早期指标 ICC 相似（0.95-0.98）。PS-late-max（8.5%）和 PS-late-peak（6.4%）的病变 wCV 与 SUV-late-max（9.7%）和 SUV-late-peak（7.2%）相似，晚期指标 ICC 相似（0.93-0.98）。病变分析中 SUV 和 PS 值的重测值有显著的偏高趋势（T-RT%Δ[95%CI]：SUV-late-max，10.0%[2.6%，17.0%]；PS-late-max，20.4%[14.3%，26.4%]），但在正常器官分析中没有这种趋势。
在[F]FDG 摄取病变中，PS 为基础的指标在晚期注射后时间点的重复性与等效的 SUV 为基础的指标相似，表明 PS 为基础的指标可能适用于跟踪肿瘤治疗的反应。然而，鉴于本研究的局限性，包括样本量小和某些指标的重测值偏高的趋势，还需要进一步验证。
