【摘要】 目的 探讨氟[18]-氟代脱氧葡萄糖(¹⁸F-FDG)正电子发射计算机断层扫描/X线计算机断层扫描（PET/CT）显像对可疑放射性碘难治性分化型甲状腺癌（RAIR-DTC）的诊断价值。方法 回顾性研究2012年1月至2020年10月期间，因可疑放射性碘难治性分化型甲状腺癌，在西安交通大学第一附属医院行¹⁸F-FDG PET/CT显像的患者49例。评估¹⁸F-FDG PET/CT显像对可疑复发或转移灶的诊断效能，及治疗方案的改变。结果 纳入DTC术后血清甲状腺球蛋白阳性而全身显像阴性（Tg+/WBS-）患者，结果表明¹⁸F-FDG PET/CT显像对复发或转移灶有较高的诊断效能（灵敏度、特异性和准确率分别为94.7%、68.8%和87.0%）。显像阳性组血清Tg水平明显高于显像阴性组（中位数：107.30ng/mL vs 3.89ng/mL;范围：1.45～21 755.00ng/mL vs 1.08～80.75ng/mL,P=0.002）,截断值研究显示当血清Tg水平为19.96ng/mL时，¹⁸F-FDG PET/CT显像灵敏度和特异性分别达到80.0%和78.6%。同时，血清甲状腺球蛋白抗体（TgAb）水平在显像阳性组及阴性组间有类似表现，阳性组TgAb水平明显高于阴性组（18.5±12.0 vs 13.0±4.0,P=0.014）,当血清TgAb达到截断值11.81 IU/mL时，¹⁸F-FDG PET/CT显像的灵敏度和特异性分别为70.0%和64.3%。SUVmax在经金标准诊断为DTC复发/转移灶和阴性病灶间差异也存在统计学意义（P<0.001）,当SUVmax达到截断值6.605时，¹⁸F-FDG PET/CT显像的特异性达100.0%,灵敏度为44.7%。36例经金标准诊断为真阳性患者中，72.2%（26/36例）的患者显像后改变治疗方案，其中10例全身多发转移灶患者考虑存在碘难治性分化型甲状腺癌灶，及时启动靶向药物治疗。结论 ¹⁸F-FDG PET/CT显像对可疑存在复发或转移的DTC患者有较高的诊断效能；当患者血清Tg水平达到19.96ng/mL或血清TgAb水平达到11.81 IU/mL时，¹⁸F-FDG PET/CT显像可用于复发或转移灶的诊断，¹⁸F-FDG PET/CT显像有助于碘难治性分化型甲状腺癌诊断，部分患者通过显像可能及时开启靶向治疗。更多还原

【Abstract】 Objective The aim of this study was to explore the diagnostic value of ¹⁸F-fluorodeoxyglucose(¹⁸F-FDG) positron emission computed tomography（PET/CT） imaging in suspected radioactive iodine refractory differentiated thyroid cancer（RAIR-DTC）.Methods A retrospective study was conducted among 49 postoperative patients with suspected RAIR-DTC who underwent ¹⁸F-FDG PET/CT imaging from January, 2012 to October, 2020 at the First Affiliated Hospital of Xi’an Jiaotong University. A total of 54 imaging sessions were performed. The diagnostic efficacy of 18F-FDG PET/CT imaging for suspected recurrent or metastatic lesions and changes in treatment plans were investigated.Results According to the golden criteria, the sensitivity, specificity and accuracy of ¹⁸F-FDG PET/CT for patient with Tg+/WBS-were 94.7%、68.8% and 87.0%, respectively, indicating a high diagnostic efficiency. The serum Tg of patients with positive ¹⁸F-FDG PET/CT was significantly higher than that of patients with negative ¹⁸F-FDG PET/CT findings（P=0.002, Median: 107.30ng/mL vs 3.89ng/mL;Rang: 1.45-21755.00ng/mL vs 1.08-80.75ng/mL）. When Tg was 19.96ng/mL, ¹⁸F-FDG PET/CT had a diagnostic sensitivity and specificity of 80.0% and 78.6%, respectively. In addition, TgAb showed similar manifestations between the positive and negative imaging groups. Compared with negative imaging group, the positives had a much higher serum TgAb（18.5±12.0 vs 13.0±4.0,P=0.014）. When serum TgAb reached the cut-off value of 11.81IU/mL, ¹⁸F-FDG PET/CT had a diagnostic sensitivity of 70.0% and specificity of 64.3%. A significant difference of SUVmax between recurrent or metastatic and non-recurrent or non-metastatic was found（P<0.001）. According to ROC curve, the cutoff value of SUVmax was 6.605, with sensitivity of 44.7% and specificity of 100%. Among 36 patients diagnosed as true positive by the gold standard, 72.2%（26/36） of them changed their treatment plan after imaging. Among them, 10 patients with multiple systemic metastases were considered to have iodine refractory differentiated thyroid cancer lesions, and targeted drug therapy was initiated.Conclusion ¹⁸F-FDG PET/CT has a good diagnostic efficiency for suspected DTC patients with recurrence or metastasis; When serum Tg level reach 19.96ng/mL or serum TgAb level reach 11.81IU/mL, ¹⁸F-FDG PET/CT imaging can be used for the diagnosis of recurrent or metastatic lesions. ¹⁸F-FDG PET/CT imaging is helpful in the diagnosis of iodine refractory differentiated thyroid cancer, and some patients may change their treatment decisions through imaging process.更多还原