Faculty of Medicine, University of Toronto, Toronto, ON, Canada.
AJR Am J Roentgenol. 2013 Feb;200(2):408-13. doi: 10.2214/AJR.12.8930.
The utility of dual-time-point (18)F-FDG PET/CT in differentiating benign from malignant processes in pediatric patients was assessed.
Twenty-one patients (13 girls and eight boys; age range, 1-17 years) with suspected malignancy underwent dual-time-point FDG PET/CT. Scan 1 was performed at approximately 60 minutes after i.v. injection of 5.18 MBq/kg of FDG, and scan 2 was performed at 121 ± 43 minutes after the first scan. Regions of interest were overlaid onto each non-attenuated-corrected image, and semiquantitative analysis was performed using the standardized uptake value (SUV) obtained from early and delayed images. A retention index was calculated according to the following equation: [(delayed SUV - early SUV) / early SUV] × 100. Results were compared prospectively in relation to pathologic examination or other conventional radiologic imaging or clinical follow-up. A retention index of 10% or higher was chosen as a cutoff for differentiating malignant from benign entities.
For patients with malignant disease, the average SUV increased from 7.3 ± 1.2 to 10.9 ± 2.7 between the two time points, whereas the SUV changed from 4.5 ± 0.8 to 4.2 ± 1.0 for patients with benign lesions. The average retention index was 37.1% ± 10.8% for patients with malignant lesions versus -9.9% ± 7.1% for benign lesions (p < 0.01). With a cutoff value of 10% or higher for the retention index, the sensitivity and specificity of dual-time-point FDG PET/CT were 77% and 80%, respectively.
These data show that dual-time-point FDG PET/CT is useful in distinguishing malignant from benign processes in pediatric patients.
评估双时相（18）F-FDG PET/CT 在鉴别儿科患者良恶性病变中的作用。
21 例（女 13 例，男 8 例；年龄 1-17 岁）疑似恶性肿瘤的患者行双时相 FDG PET/CT 检查。静脉注射 5.18MBq/kg FDG 后约 60 分钟行扫描 1，扫描 1 后 121±43 分钟行扫描 2。在每个非衰减校正图像上叠加感兴趣区，并使用早期和延迟图像获得的标准化摄取值（SUV）进行半定量分析。根据以下公式计算滞留指数：[(延迟 SUV-早期 SUV)/早期 SUV]×100。前瞻性比较结果与病理检查或其他常规影像学检查或临床随访。选择滞留指数 10%或更高作为鉴别良恶性实体的截止值。
恶性疾病患者的 SUV 平均值从两个时间点的 7.3±1.2 增加到 10.9±2.7，而良性病变患者的 SUV 从 4.5±0.8 增加到 4.2±1.0。恶性病变患者的平均滞留指数为 37.1%±10.8%，良性病变患者为-9.9%±7.1%（p<0.01）。以滞留指数 10%或更高为截止值，双时相 FDG PET/CT 的灵敏度和特异性分别为 77%和 80%。
这些数据表明，双时相 FDG PET/CT 有助于鉴别儿科患者的良恶性病变。
