Department of Pulmonary Diseases, VU University Medical Center, Amsterdam, The Netherlands.
J Nucl Med. 2012 May;53(5):701-8. doi: 10.2967/jnumed.111.095299. Epub 2012 Apr 10.
PET with the glucose analog (18)F-FDG is increasingly used to monitor tumor response to therapy. To use quantitative measurements of tumor (18)F-FDG uptake for assessment of tumor response, the repeatability of this quantitative metabolic imaging method needs to be established. Therefore, we determined the repeatability of different standardized uptake value (SUV) measurements using the available data.
A systematic literature search was performed to identify studies addressing (18)F-FDG repeatability in malignant tumors. The level of agreement between test and retest values of 2 PET uptake measures, maximum SUV (SUV(max)) and mean SUV (SUV(mean)), was assessed with the coefficient of repeatability using generalized linear mixed-effects models. In addition, the influence of tumor volume on repeatability was assessed. Principal component transformation was used to compare the reproducibility of the 2 different uptake measures.
Five cohorts were identified for this metaanalysis. For SUV(max) and SUV(mean), datasets of 86 and 102 patients, respectively, were available. Percentage repeatability is a function of the level of uptake. SUV(mean) had the best repeatability characteristics; for serial PET scans, a threshold of a combination of 20% as well as 1.2 SUV(mean) units was most appropriate. After adjusting for uptake rate, tumor volume had minimal influence on repeatability.
SUV(mean) had better repeatability performance than SUV(max). Both measures showed poor repeatability for lesions with low (18)F-FDG uptake. We recommend the evaluation of biologic effects in PET by reporting a combination of minimal relative and absolute changes to account for test-retest variability.
正电子发射断层扫描（PET）使用葡萄糖类似物（18）F-FDG 越来越多地用于监测肿瘤对治疗的反应。为了使用肿瘤（18）F-FDG 摄取的定量测量来评估肿瘤反应，需要确定这种定量代谢成像方法的可重复性。因此，我们使用现有数据确定了不同标准化摄取值（SUV）测量的可重复性。
进行了系统的文献检索，以确定研究恶性肿瘤（18）F-FDG 重复性的研究。使用广义线性混合效应模型，通过可重复性系数评估 2 种 PET 摄取测量（最大 SUV（SUV(max)）和平均 SUV（SUV(mean)）的测试值和复测值之间的一致性。此外，还评估了肿瘤体积对可重复性的影响。主成分变换用于比较两种不同摄取测量的重现性。
对这项荟萃分析确定了 5 个队列。对于 SUV(max)和 SUV(mean)，分别有 86 和 102 个患者的数据集可用。重复性百分比是摄取水平的函数。SUV(mean)具有最佳的可重复性特征；对于连续 PET 扫描，20%的组合以及 1.2 SUV(mean)单位的阈值是最合适的。在调整摄取率后，肿瘤体积对可重复性的影响最小。
SUV(mean)比 SUV(max)具有更好的可重复性。对于摄取率较低的病变，两种测量方法的可重复性都较差。我们建议通过报告最小相对和绝对变化的组合来评估 PET 中的生物学效应，以考虑测试-复测的变异性。
