Treatment monitoring by 18F-FDG PET/CT in patients with sarcomas:: Interobserver variability of quantitative parameters in treatment-induced changes in histopathologically responding and nonresponding tumors
Treatment monitoring by 18F-FDG PET/CT in patients with sarcomas:: Interobserver variability of quantitative parameters in treatment-induced changes in histopathologically responding and nonresponding tumors
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DOI：
10.2967/jnumed.107.050187
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发表时间：
2008-07-01
影响因子：
9.3
通讯作者：
Weber, Wolfgang A.
中科院分区：
文献类型：
--
作者：
Benz, Matthias R.;Evilevitch, Vladimir;Weber, Wolfgang A.
使用F-18-FDG PET测量肿瘤葡萄糖需要在机构内和机构间标准化。使用18F-FDG PET测量肿瘤糖代谢活性随癌症治疗的变化，使用各种参数。然而，尚不清楚哪一种方法在观察者之间提供了最低的可变性。在肉瘤中，了解定量参数的观察者之间的可变性是很重要的，因为这些肿瘤通常很大，并且表现出不均匀的F-18-FDG摄取。方法：33例高级别肉瘤患者（男性116例，女性17例，平均年龄47 +/- 18岁）在新辅助化疗前后行F-18-FDG PET/CT扫描。两名独立研究人员测量了治疗前后扫描的以下参数：最大标准化摄取值（SUVmax）、峰值SUV （SUVpeak）、平均SUV （SUVmean）、自动定义体积内的SUV （SUVauto）和肿瘤与背景比（TBR）。采用一致性相关系数（CCC）、变异效应系数和Bland-Altman图比较不同参数的变异性。结果：基线SUVmax、SUVpeak、SUVmean、SUVauto和TBR平均分别为10.36、7.78、4.13和6.22 g/mL和14.67。处理后分别降至5.36、3.80、11.79、3.25 g/mL和6.62 g/mL。SUVmax、SUVpeak和SUVauto测量值及其变化可重复（CCC >= 0.98）。然而，SUVauto在有反应和无反应的肿瘤之间很难区分。F-18-FDG的高肿瘤内异质性导致阈值算法经常失败，这需要人工校正，从而导致SUVmean的较高观察者间变异性（随访和变化的CCCs分别为0.96和0.91,P < 0.005）。tbr的变异性也明显高于SUVpeak（随访和变化的CCCs分别为0.94和0.86,P < 0.005）。结论：SUVmax和SUVpeak提供了最可靠的肿瘤糖代谢测量方法。用半自动阈值法描绘整个肿瘤体积并没有降低SUV测量值的可变性。tbr明显比绝对suv更依赖观察者。这些发现应该被用于临床F-18-FDG PET/CT试验的标准化。
Measurements of tumor glucose use by F-18-FDG PET need to be standardized within and across institutions. Various parameters are used for measuring changes in tumor glucose metabolic activity with 18F-FDG PET in response to cancer treatments. However, it is unknown which of these provide the lowest variability between observers. Knowledge of the interobserver variability of quantitative parameters is important in sarcomas as these tumors are frequently large and demonstrate heterogeneous F-18-FDG uptake. Methods: A total of 33 patients (116 men, 17 women; mean age, 47 +/- 18 y) with high-grade sarcomas underwent F-18-FDG PET/CT scans before and after neoadjuvant chemotherapy. Two independent investigators measured the following parameters on the pretreatment and posttreatment scans: maximum standardized uptake value (SUVmax), peak SUV (SUVpeak), mean SUV (SUVmean), SUVmean in an automatically defined volume (SUVauto), and tumor-to-background ratio (TBR). The variability of the different parameters was compared by concordance correlation coefficient (CCC), variability effect coefficient, and Bland-Altman plots. Results: Baseline SUVmax, SUVpeak, SUVmean, SUVauto, and TBR averaged 10.36, 7.78, 4.13, and 6.22 g/mL and 14.67, respectively. They decreased to 5.36, 3.80,11.79, and 3.25 g/mL and 6.62, respectively, after treatment. SUVmax, SUVpeak, and SUVauto measurements and their changes were reproducible (CCC >= 0.98). However, SUVauto poorly differentiated between responding and nonresponcling tumors. The high intratumoral heterogeneity of F-18-FDG resulted in frequent failure of the thresholding algorithm, which necessitated manual corrections that in turn resulted in a higher interobserver variability of SUVmean (CCCs for follow-up and change were 0.96 and 0.91, respectively; P < 0.005). TBRs also showed a significantly higher variability than did SUVpeak (CCCs for follow-up and change were 0.94 and 0.86, respectively; P < 0.005). Conclusion: SUVmax and SUVpeak provided the most robust measurements of tumor glucose metabolism in sarcomas. Delineation of the whole-tumor volume by semiautomatic thresholding did not decrease the variability of SUV measurements. TBRs were significantly more observer-dependent than were absolute SUVs. These findings should be considered for standardization of clinical F-18-FDG PET/CT trials.