促甲状腺激素水平对18F-FDG PET／CT诊断分化型甲状腺癌失分化后复发及转移灶的影响

目的探讨促甲状腺激素（thyroid stimulating hormone，TSH）水平对18F-氟代脱氧葡萄糖（18F—fluorodeoxyglucose，18F—FDG）正电子发射计算机断层显影术（positron emission tomography／eomputed tomograpby，PET／CT）诊断甲状腺球蛋白（thyroglobalin，TG）阳性而131I-诊断剂量全身显像（131I-diagnos—ticwhole—body scanning，131I-dWBS）阴性的分化型甲状腺癌（differentiated thyroid carcinoma，DTC）失分化后复发和转移灶的影响。方法征得患者同意后，将60例欲行18F-FDG PET／CT检测的分化型甲状腺癌术后患者（TG阳性而131I-dWBS阴性）随机分为低TSH组（30例）和高TSH组（30例）。以术后组织病理学或至少6个月的临床和影像学随访结果为诊断病灶性质的标准，得出其阳性预测值（positive predictive value，PPV），比较TSH水平高低对18F—FDG PET／CT检测结果的影响；分析TG水平与放射性浓聚病灶的标准摄取值（standardized uptake Value，SUV）间的关系。结果高TSH水平及低TSH水平下18F—FDG PET／CT诊断DTC复发和转移灶的阳性预测值分别为96．7％和80．0％（P〈0．05）；患者TG水平与SUV呈正相关。结论18F—FDG PET／CT对于TG阳性而131I-dWBS阴性DTC患者复发和转移灶的诊断，在高TSH水平下较低TSH水平有更高的敏感性与特异性，此可能与TSH刺激肿瘤组织对18F—FDG的摄取相关。

The influence of TSH expression on the diagnotic efficiency of 18F-FDG PET/CT in the detection of recurrence/metastasis of dedifferentiated thyroid carcinoma

Objective To explore the influence of thyroid stimulating hormone （TSH） expression on the diagnostic efficiency of 18 F-FDG PET/CT in the detection of recurrence or metastasis of differentiated thyroid carcinoma（DTC） in patients with elevated expression of thyroglobulin（TG） and negative 131I-diagnostie whole body scan （131I-dWBS）. Methods 30 DTC patients with high TSH expression and another 30 patients with low TSH （without or with administration of thyradin） with high TG expression but negative 131I-dWBS were detected by PET/CT. The diagnosis standard was based on histopathologic findings or clinical/imaging follow-up results within 6 months. The positive predictive values（PPVs） were obtained and the influence of TSH expression on the diagnostic efficiency of PET/CT was compared ,furthermore, the relationship between TG and standardized uptake values（SUVs） of 18 F-FDG was analyzed as well. Results Eneouragingly, for detecting the reeurrence/metastasis of dedifferentiated thyroid carcinoma,the PPV of PET/CT in the high and low TSH groups were 96.7% and 80.0%, respectively, showed a significant difference（ P 〈 0.05 ）. Moreover, the TG was positively correlated with SUVs. Conclusions The diagnostic efficiency of PET/CT in high TSH group is stronger than that in low TSH group for detecting the recurrences/metastases of DTC in patients with high TG levels bat negetive 131I-dWBS, which is probably due to the elevated uptake of is F-FDG stimulated bv TSH.