18F-FDG PET双时相显像在鉴别良恶性病变中的价值

目的探讨18F-FDGPET双时相显像在鉴别良、恶性病变中的临床价值。方法对28例原发性肺癌、18例消化系恶性肿瘤、13例其他恶性肿瘤和37例良性病变患者于静脉注射18F-FDG185~370MBq后45min和2.5~3h分别进行早期和延迟双时相PET/CT显像,并对重建后的图像进行定性与定量评价,获得病灶区不同时相的平均SUV(SUVmean)和最大SUV(SUVmax),并以延迟显像SUV值的变化大于10%判断为增高或减低。结果在肺癌组28例中,早期显像24例SUV明显增高(85.7%),延迟显像除1例SUV值无变化外,其余均有不同程度增高,4例早期显像结节处为可疑阳性(SUVmax为1.5~2.1)者,延迟显像3例明显增高,1例SUV未见明显增加,延迟显像阳性率为96.4%;消化系统恶性肿瘤18例,其中17例早期SUV升高(94.4%),1例为阴性,延迟显像18例均增高;其他肿瘤13例,早期均为阳性,延迟显像SUV进一步增高。37例良性病变早期有12例SUV增高(>2.5),延迟显像4例仍为阳性。本文病例早期显像总的的敏感性、特异性、准确性、阳性预测值和阴性预测值分别为91.5%、67.6%、82.3%、68.4%和83.3%;延迟显像分别为98.3%、86.5%、93.8%、92.1%和97.0%。结论18F-FDGPET双时相显像对于鉴别肿瘤的良、恶性有一定价值,几乎所有的早期显像为阳性的恶性肿瘤,延迟显像有进一步摄取增高,但部分良性病灶也具有相同特征。

The value of dual time point 18F-FDG PET imaging for the differentiation between malignant and benign lesions

Objective To assess the clinical value of dual-time point ~ 18 F- FDG PET imaging for differentiating malignant from benign lesions. Methods Twenty-eight patients with primary lung cancer, 18 patients with digestive system carcinoma, 13 patients with other kind of malignant tumors, and 37 patients with benign lesions underwent PET-CT at 2 time points: scan 1 at 45 min and scan 2 at 150-180 min after the intravenous injection of 185-370 MBq ~ 18 F- FDG. Reconstructed images were evaluated qualitatively and quantitatively. The maximum standardized uptake value (SUV_ max ) and average SUV (SUV_ mean ) within the lesions were calculated for both time points. By adopting a SUV change >10% between the first and second scans was as a criterion for increase and decrease. Results Twenty-four of 28 primary lung cancers had SUV>2.5 at scan 1. Among them, 23 showed increase uptake and the other one showed no change of SUV in the delayed imaging (scan 2). The other 4 primary lung tumors had SUVs between 1.5 and 2.5 at scan 1 which showed suspected positive, three of whose SUVs increased at time point 2. Seventeen of 18 malignant lesions in digestive system showed SUV>2.5, the other one showed negative at scan 1, and all showed increase in SUV at scan 2. Of 13 other kinds of tumors, all had SUV> 2.5 at scan 1 and SUVs increased at time point 2. For the benign lesions, 12 showed positive at early and 4 positive in delayed images. The sensitivity, specificity, accuracy, positive and negative predicted value for the early and delayed imaging were 91.5%, 67.6%, 82.3%, 68.4% and 83.3% and 98.3%, 86.5%, 93.8%, 92.1% and 97.0%, respectively. Conclusion These data showed that dual time imaging appeared to be helpful for differentiating benign lesions from malignant lesions. Almost all malignant tumors had SUV>2.5 at scan 1 and showed further increase at scan 2, but some benign lesions also had this kind of character.