18F-FDG PET/CT显像在Tg阳性131I全身显像阴性的分化型甲状腺癌患者中的应用价值

The application value of 18F-FDG PET/CT in patients with differentiated thyroid cancer of high thyroglobulin level and negative 131I whole body scan

目的：评判18F-FDG PET/CT作为一个常规的检查工具对临床诊断怀疑为分化型甲状腺癌（DTC）复发、伴有甲状腺球蛋白（Tg）升高且131I全身显像阴性患者的价值。方法对甲状腺全切后经放射性131I去除治疗后的32例Tg升高伴全身131I显像阴性的DTC患者行18F-FDG PET/CT显像。按照Tg水平将患者分2组：H组21例（＞10 ng/ml）和L组11例（2～10 ng/ml）。分别采用超声、病理学检查和临床随访对结果进行验证，评估18F-FDG PET/CT在DTC中的诊断价值。结果32例患者中，20例18F-FDG PET/CT显像阳性，其中18例真阳性，2例假阳性。在18例真阳性患者中，15例是局部复发，6例有远处转移，3例患者同时有局部侵犯伴远处转移。12例18F-FDG PET/CT显像阴性，其中真阴性4例，假阴性8例，总体灵敏度、特异度和准确率分别为69．2%、66．7%和68．8%。，H组的18F-FDG PET/CT显像灵敏度（80%）、特异度（100%）和准确率（80．9%）跟L组（33．3%、60．0%和45．5%）比较均显著增加。32例患者中的18例（56．2%）的临床处理策略发生了改变，12例（37．5%）进行了指导性根治手术。结论18F-FDG PET/CT可以探测和准确定位DTC中Tg升高且131I全身显像阴性的区域复发和远处转移，因此可推荐为常规的诊断工具。

Objective To estimate the valuate of 18F-FDG PET/CT as a routine examination for the patients with suspected differentiated thyroid carcinoma （DTC） recurrence, accompanied by the increase of thyroglobulin （Tg） and negative 131I whole body scan. Method 32 patients who suffered from DTC receiving post-operative 131I therapy, with increase of Tg and negative 131I whole body scan, were performed 18F-FDG PET/CT, and follow-up continued. Patients were divided into two groups according to the level of Tg： H group （Tg〉10 ng/ml）and L group （Tg＆lt;10 ng/ml）. Histopathological examination, ultrasound examination and clinical follow-up were used to verify the result, and assess the clinical value of PET/CT. Result PET/CT imaging results indicated that among 32 patients, there were 20 positive （18 true-positive and 2 false-positive） and 12 negative （4 true-negative and 8 false-negative）. Among 18 patients with true positive, 15 cases with local disease, 6 cases with distant metastasis, and 3 patients with both local invasion and distant metastasis. The overall sensitivity, specificity and accuracy were 69.2%, 66.7%and 68.8%, respectively. Compared with the L group, H group developed higher sensitivity （80%versus 33.3%）, specificity （100%versus 60%） and accuracy （80.9%versus 45.5%）. In 32 patients, 18 cases（56.2%） changed the strategies of clinical treatment, and 12 cases（37.5%） were received the radical operation under guidance. Conclusion 18F-FDG PET/CT can detect and locate accurately for the regional metastasis and recurrence of patients with DTC, accompanied by the increase of serum Tg and negative 131I whole body scan. Therefore, it can be recommended as a routine diagnostic tool.