Xiu Yan, Bhutani Chirdeep, Dhurairaj Thiruvenkatasamy, Yu Jian Q, Dadparvar Simin, Reddy Swapna, Kumar Rakesh, Yang Hua, Alavi Abass, Zhuang Hongming
Department of Radiology, University of Pennsylvania School of Medicine, Hospital of the University of Pennsylvania, Philadelphia, PA, USA.
Clin Nucl Med. 2007 Feb;32(2):101-5. doi: 10.1097/01.rlu.0000252457.54929.b7.
FDG PET has high accuracy in the evaluation of lung nodules. A standardized uptake value (SUV) > or =2.5 is frequently used as a criterion for malignancy in this setting. However, some malignant nodules have only mild FDG activity with a SUV less than 2.5. Assessment of the etiology of lung nodules with only mild metabolic activity remains difficult. This study was undertaken to compare the accuracy of dual-time point and standard single-time FDG PET imaging in the evaluation of such lung nodules.
Four hundred fifty-seven dual-time FDG PET scans for lung nodules were retrospectively analyzed. Among them, 46 met the selection criteria and were included for the final analysis. Five methods of interpreting FDG PET results were compared. These methods included visual analysis for both initial and delayed images; SUV analysis for both initial and delayed images in which a SUV of 2.5 is regarded as criteria for malignancy; and finally, the retention index analysis in which a 10% increase in SUV on the delayed images was regarded as an indication of malignancy.
The lowest accuracies came from the visual and single SUV analysis on the initial images. The visual and single SUV analyses on the delayed images produced increased accuracy. The highest accuracy (84.8%) was obtained when a retention index of more than 10% was used as criteria for malignancy.
Dual-time FDG PET imaging has the potential for improving accuracy of a test in the evaluation of lung nodules with only borderline levels of increased metabolic activity.
氟代脱氧葡萄糖正电子发射断层扫描（FDG PET）在评估肺结节方面具有很高的准确性。在这种情况下，标准化摄取值（SUV）≥2.5常被用作恶性肿瘤的标准。然而，一些恶性结节的FDG活性仅为轻度，SUV小于2.5。评估代谢活性仅为轻度的肺结节的病因仍然困难。本研究旨在比较双时相和标准单时相FDG PET成像在评估此类肺结节中的准确性。
对457例肺结节的双时相FDG PET扫描进行回顾性分析。其中，46例符合选择标准并纳入最终分析。比较了5种解释FDG PET结果的方法。这些方法包括对初始图像和延迟图像的视觉分析；对初始图像和延迟图像的SUV分析，其中将SUV 2.5作为恶性肿瘤的标准；最后是留存指数分析，其中延迟图像上SUV增加10%被视为恶性肿瘤的指标。
初始图像的视觉分析和单SUV分析准确性最低。延迟图像的视觉分析和单SUV分析准确性有所提高。当以留存指数大于10%作为恶性肿瘤标准时，准确性最高（84.8%）。
双时相FDG PET成像在评估代谢活性仅为临界升高水平的肺结节时，有可能提高检测的准确性。
