Department of Diagnostic Radiology, Queen Mary Hospital, University of Hong Kong, Pokfulam, Hong Kong.
Clin Nucl Med. 2013 Feb;38(2):e60-5. doi: 10.1097/RLU.0b013e318266d53e.
The differentiation between tumor and bland thromboses is important as the management differs. Retrospectively, we aim to evaluate the utility of FDG PET in detecting and differentiating tumor from bland thromboses and if FDG PET provides additional value to contrast-enhanced CT for tumor thrombus detection.
Twenty-four sites of venous thromboembolism, detected on PET/CT, were retrospectively reviewed. Classification of type of thrombosis was based on histology and radiological follow-up. We evaluated the presence of contrast-enhanced CT findings that were suggestive of tumor thrombosis; sign of invasion, neovascularity, and enhancement. Metabolic activity by means of SUV(max) was measured by drawing ROI at the site of thrombosis. Mann-Whitney U test was used to compare the mean SUV(max) between thromboses and internal references. We used ROC analysis to identify the optimal cutoff value of SUV(max) for detection of tumor thrombosis.
Twenty-four sites of venous thromboembolism were identified in 15 patients. All tumor thromboses demonstrated at least 1 positive sign on contrast-enhanced CT, whereas 33% of bland thromboses had the same finding. The difference between tumor and bland thrombus SUV(max) was statistically significant (P < 0.005). On ROC analysis, a cutoff of SUV(max) 2.25 (sensitivity, 78%; specificity, 100%) was suggested to differentiate tumor from bland thrombosis.
PET/CT is able to differentiate tumor from bland thrombosis, with an optimal cutoff value of SUV(max) 2.25. The metabolic information increases the diagnostic accuracy of tumor thrombus and is a useful adjunct to the described features on contrast-enhanced CT.
区分肿瘤性血栓和非肿瘤性血栓非常重要，因为两者的处理方法不同。本研究旨在回顾性评估 FDG PET 在检测和区分肿瘤性血栓与非肿瘤性血栓中的作用，以及 FDG PET 是否为 CT 增强扫描在检测肿瘤性血栓方面提供了额外的价值。
回顾性分析 24 例经 PET/CT 检测到的静脉血栓栓塞部位。根据组织学和影像学随访结果对血栓类型进行分类。我们评估了 CT 增强扫描是否存在提示肿瘤性血栓的表现，包括侵犯、新生血管和强化。通过在血栓部位绘制 ROI 来测量代谢活性（SUV(max)）。采用 Mann-Whitney U 检验比较血栓与内部参考部位的 SUV(max)均值。采用 ROC 分析确定 SUV(max)最佳截断值，以用于检测肿瘤性血栓。
在 15 例患者中共发现 24 处静脉血栓栓塞部位。所有肿瘤性血栓在 CT 增强扫描上至少有 1 个阳性表现，而非肿瘤性血栓的这一比例为 33%。肿瘤性血栓和非肿瘤性血栓 SUV(max)之间的差异具有统计学意义（P < 0.005）。ROC 分析显示，SUV(max)截断值为 2.25（敏感性为 78%，特异性为 100%）可用于区分肿瘤性血栓和非肿瘤性血栓。
PET/CT 能够区分肿瘤性血栓和非肿瘤性血栓，SUV(max)最佳截断值为 2.25。代谢信息增加了肿瘤性血栓的诊断准确性，是 CT 增强扫描描述特征的有用补充。
