18F-FDG PET/CT检测131I-治疗剂量全身显像阴性而甲状腺球蛋白阳性分化型甲状腺癌复发和转移

目的 分析不同大小、位置甲状腺微小乳头状癌（PTMC）的声像图特征，探讨纵横比（A/T）与甲状腺被膜侵犯的关系。方法 收集经病理证实的407例PTMC患者（495个结节），分为最大径 ≤ 0.5 cm组和最大径>0.5 cm组，观察结节的声像学特征，并分析A/T与被膜侵犯的关系。结果 2组间血流类型、病灶与被膜关系、钙化、形态、A/T差异均有统计学意义（P均<0.05）。与被膜关系密切且A/T ≥ 1的结节中，最大径>0.5 cm组被膜侵犯率（117/185，63.24%）高于最大径 ≤ 0.5 cm组（25/61，40.98%，P<0.01）。以A/T ≥ 1判断最大径 ≤ 0.5 cm组和最大径>0.5 cm组与被膜关系密切的结节出现被膜侵犯的敏感度为89.29%、73.58%，特异度为29.41%、37.61%；紧邻被膜和突破被膜的结节中，A/T ≥ 1与A/T<1的结节间被膜侵犯率差异均无统计学意义（P均>0.05）；接触被膜的结节中，A/T ≥ 1的结节被膜侵犯率（46/67，68.66%）高于A/T<1的结节（10/27，37.04%）。以A/T ≥ 1判断接触被膜的结节出现被膜侵犯的敏感度为82.14%，特异度为44.74%。结论 超声可观察PTMC大小、A/T及病灶与被膜的关系，为判断PTMC是否出现被膜侵犯提供诊断依据。

18F-FDG PET/CT in detection of recurrence and/or metastasis of differentiated thyroid carcinoma in patients with elevated serum thyroglobulin levels and negative 131I post-therapy whole body scan

Objective To investigate the diagnostic value and the impact on treatment decision of ¹⁸F-FDG PET/CT in differentiated thyroid carcinoma (DTC) patients with elevated serum thyroglobulin (Tg) levels and negative radioiodine ¹³¹I post-therapy whole body scan (¹³¹I-RxWBS). Methods Totally 72 patients with DTC who had elevated serum Tg levels and negative ¹³¹I-RxWBS were enrolled, and ¹⁸F-FDG PET/CT was performed. The imaging results of ¹⁸F-FDG PET/CT were compared with the clinical results of surgical pathology or 6 to 36 months follow-up. The diagnostic efficacy of ¹⁸F-FDG PET/CT in detection of recurrence and/or metastasis of DTC with elevated Tg levels and negative ¹³¹I-RxWBS was evaluated. Results The accuracy, sensitivity, specificity, positive prediction value and negative prediction value of ¹⁸F-FDG PET/CT in diagnosis of DTC with elevated Tg levels and negative ¹³¹I-RxWBS was 83.33% (60/72), 89.47% (34/38), 76.47% (26/34), 80.95% (34/42) and 86.67% (26/30), respectively. ¹⁸F-FDG PET/CT changed the treatment strategies of 35 patients (35/72, 48.61%) among 72 patients, while recurrence or metastasis of DTC was not found during clinical follow-up in 23 of these 35 patients (23/35, 65.71%) who underwent reoperation, but was detected in the other 12 patients (12/35, 34.29%). Conclusion ¹⁸F-FDG PET/CT is a valuable method for detection of recurrence and/or metastasis of DTC with elevated Tg levels and negative ¹³¹I-RxWBS, also for guiding the follow-up treatment strategy.