Department of Imaging, H Lee Moffitt Cancer Center and Research Institute, Tampa, FL 33612-9416, USA.
Clin Nucl Med. 2013 Mar;38(3):175-82. doi: 10.1097/RLU.0b013e318279ffdf.
Measurement variance affects the clinical effectiveness of PET-based measurement as a semiquantitative imaging biomarker for cancer response in individual patients and for planning clinical trials. In this study, we measured test-retest reproducibility of SUV measurements under clinical practice conditions and recorded recognized deviations from protocol compliance.
Instrument performance calibration, display, and analyses conformed to manufacture recommendations. Baseline clinical (18)F-FDG PET/CT examinations were performed and then repeated at 1 to 7 days. Intended scan initiation uptake period was to repeat the examinations at the same time for each study after injection of 12 mCi FDG tracer. Avidity of uptake was measured in 62 tumors in 21 patients as SUV for maximum voxel (SUV(max)) and for a mean of sampled tumor voxels (SUV(mean)).
The range of SUV(max) and SUV(mean) was 1.07 to 21.47 and 0.91 to 14.69, respectively. Intraclass correlation coefficient between log of SUV(max) and log of SUV(mean) was 0.93 (95% confidence interval [CI], 0.88-0.95) and 0.92 (95% CI, 0.87-0.95), respectively.Correlation analysis failed to show an effect on uptake period variation on SUV measurements between the 2 examinations, suggesting additional sources of noise.The threshold criteria for relative difference from baseline for the 95% CI were ± 49% or ± 44% for SUV(max) or SUV(mean), respectively.
Variance of SUV for FDG-PET/CT in current clinical practice in a single institution was greater than expected when compared with benchmarks reported under stringent efficacy study settings. Under comparable clinical practice conditions, interpretation of changes in tumor avidity in individuals and assumptions in planning clinical trials may be affected.
测量变异会影响基于 PET 的测量作为癌症患者个体反应和临床试验计划的半定量成像生物标志物的临床效果。在这项研究中，我们测量了临床实践条件下 SUV 测量的复测再现性，并记录了与协议依从性的公认偏差。
仪器性能校准、显示和分析符合制造商的建议。进行基线（18）F-FDG PET/CT 检查，然后在 1 至 7 天内重复进行。预期的扫描开始摄取期是在每个研究中注射 12 mCi FDG 示踪剂后，为每个研究同时重复检查。21 名患者的 62 个肿瘤的摄取活性分别以最大体素 SUV(max)和采样肿瘤体素的平均值 SUV(mean)来测量。
SUV(max)和 SUV(mean)的范围分别为 1.07 至 21.47 和 0.91 至 14.69。SUV(max)和 SUV(mean)的对数之间的组内相关系数分别为 0.93(95%置信区间[CI]，0.88-0.95)和 0.92(95% CI，0.87-0.95)。相关性分析表明，摄取期变化对两次检查之间的 SUV 测量没有影响，这表明存在其他噪声源。SUV(max)或 SUV(mean)的 95% CI 的基线相对差异的阈值标准分别为±49%或±44%。
与严格疗效研究环境下报告的基准相比，在单一机构的当前临床实践中，FDG-PET/CT 的 SUV 变异大于预期。在可比的临床实践条件下，个体肿瘤活性变化的解释和临床试验计划的假设可能会受到影响。
