^(18)F-FDG PET延迟显像鉴别诊断原发性肺癌

Diagnostic value of ^(18)F-FDG PET delayed imaging for patients with primary lung cancer

目的 探讨18F 脱氧葡萄糖 (FDG)PET延迟显像对原发性肺癌和肺结核的鉴别诊断价值。方法 70例受检者分为原发性肺癌组 (2 5例 )、肺结核组 (16例 )和正常对照组 (2 9例 ) ,分别行18F FDGPET早期头部～盆腔显像和注射后 4h胸部延迟显像。计算 2次显像肺部病灶感兴趣区 (ROI)与同一平面对侧正常组织的放射性比值 (T/B)。结果 18F FDGPET显像示 2 5例原发性肺癌早期显像阳性 2 2例 ,阴性 3例 ,灵敏度、特异性和阳性预测值分别为 88 0 %、87 5 %和 91 7% ;延迟显像阳性2 3例 ,阴性 2例 ,灵敏度、特异性和阳性预测值分别为 92 0 %、93 8%和 95 8%。T/B与原发性肺癌不同组织学类型存在明显关系。肺结核组早期显像T/B为 3 6 7± 2 17,其中 2例发现FDG高摄取灶 ,假阳性率为 12 5 % ,延迟显像 1例FDG阳性 ,假阳性率为 6 3%。早期显像原发性肺癌组T/B (4 33± 3 0 0 )和肺结核组差异无显著性 (t=0 94 5 ,P =0 347) ,延迟显像原发性肺癌组T/B (7 91± 7 0 8)较早期显像增高 3 4 9± 2 6 6 ,明显高于肺结核组 (3 6 7± 1 86 ,t=4 173,P =0 0 0 0 )。肺结核组和对照组T/B (1 15± 0 31,1 0 5± 0 13)延迟与早期显像差异无显著性 (t=0 0 4 9、1 5 6 4 ,P =0 96 6、0 199)。

Objective To discuss the diagnostic value of 18 F-fluorodeoxyglucose (FDG) PET delayed imaging in primary lung cancers and distinguish them from tuberculosis. Methods 18 F-FDG PET early and 4 h delayed imaging were performed on seventy patients after intravenous injection of FDG,and the patients were defined into three groups: twenty-five subjects were with primary lung cancers,sixteen were with tuberculosis,twenty-nine were normal. Lung cancer patients were divided into subgroups of small-cell,squamous cell lung cancer and adenocarcinoma. Each image was analyzed by visual interpretation and semiquantitative method. FDG high uptake lesions as regions of interest (ROI) were drawn. ROI average FDG uptakes were evaluated and compared with that of the contralateral normal tissue (target/background,T/B) on the same plane of the images acquired at 1 and 4 h. Results Standard PET imaging with a threshold standardized uptake value (SUV) of 2.5 found 22 positive and 3 negative cases. The resultant sensitivity,specificity and positive predictive value was 88.0%(22/25),87.5%(14/16),91.7%(22/24),respectively. Delayed imaging with a threshold SUV of 2.5 and increasing the positive cut-off by 10% than before found 23 positive and 2 negative cases. The sensitivity,specificity and positive predictive value was 92.0%(23/25),93.8%(15/16)and 95.8%(23/24). The T/B ratio was closely relative to pathobiological types of primary lung cancers. In tuberculosis group,the mean SUV of lesions was 3.67±2.17. Two high-FDG-uptake cases and one positive case were found on early imagings, the mistake rate was 12.5%(2/16) and 6.3%(1/16),respectively. All the T/B ratios of the malignant lesions in lung cancer group were significantly higher at 4 h than at 1 h. In the contrary,T/B in normal and tuberculosis groups showed different uptakes of FDG at 1 and 4 h. Compared two imaging protocols,there was significant difference between lung cancer and tuberculosis group in delayed imaging ( t =4.173,P =0.000) not in early imaging ( t =0.945,P =0.347). Conclusion Delayed FDG PET imaging is a better and more reliable imaging protocol for detecting and distinguishing lung cancer.