Abstract: Objective　To evaluate the value of ultrasound-guided thyroid fine needle aspiration （FNA） in the differential diagnosis of benign and malignant thyroid nodules，and to investigate the effect of nodule size on Bethesda classification.Methods　We retrospectively analyzed the clinical data of patients who underwent ultrasound-guided thyroid FNA of thyroid nodules in the Ningbo First Hospital in 2015 and 2016，as well as the pathological results according to the Bethesda reporting system.Histopathology was used as the gold standard to judge the value of thyroid FNA in differentiating benign from malignant nodules，and the effect of nodule size on Bethesda classification was also analyzed.Results　A total of 743 patients were included，and 755 nodules were analyzed.The nodule diameter was （10.4±7.1）mm.The FNA pathological results of 755 thyroid nodules were classified according to the Bethesda reporting system：there were 81（10.7%） nodules with unsatisfactory specimens，342（45.3%） benign nodules，80（10.6%） nodules with atypia of undetermined significance （AUS），3（0.4%） follicular neoplasms，91（12.1%） suspicious malignant nodules，and 158（20.9%） malignant nodules.The rate of satisfactory specimens was 89.3%（674/755）.There were no significant differences in the rates of unsatisfactory samples，AUS and malignant nodules between ≤10 mm and >10 mm nodules （P>0.05）.There were no significant differences in the rates of unsatisfactory samples and AUS between ≤5 mm nodules and >5 mm nodules （P>0.05）.The malignant rate was lower in ≤5 mm thyroid nodules than >5 mm nodules （P<0.001）.Among 202 nodules with surgical pathological results，FNA obtained consistent results in 173 nodules.The sensitivity，specificity，accuracy，positive predictive value，and negative predictive value of FNA in the diagnosis of thyroid nodules were 94.3%（150/159），85.7%（12/14），93.6%（162/173），98.7%（150/152），and 57.1%（12/21），respectively.Conclusion　Ultrasound-guided thyroid FNA has substantial value in differentiating benign and malignant thyroid nodules，with a very high positive predictive value；nodule size does not significantly affect Bethesda cytopathological classification，and the rate of satisfactory specimens is affected by the degree of proficiency.

Key words: Thyroid nodule；Bethesda system for reporting thyroid cytopathology；Ultrasonography；Biopsy, fine-needle

摘要： 目的　评估超声引导下甲状腺细针抽吸术（FNA）鉴别诊断甲状腺良恶性结节的价值，并探讨结节大小对Bethesda分类结果的影响。方法　回顾性分析2015—2016年因甲状腺结节在宁波市第一医院行超声引导下甲状腺FNA患者的临床资料及按照Bethesda报告系统分类的细胞病理学结果。以组织病理学为金标准，判断甲状腺FNA在良恶性结节鉴别诊断作用，并分析结节大小对Bethesda分类结果的影响。结果　共纳入743例患者755个结节，结节直径为（10.4±7.1）mm。755个甲状腺结节FNA细胞病理学参考Bethesda报告系统分类：标本不满意81个（10.7%），良性结节342个（45.3%），意义不明确的细胞非典型（AUS）病变80个（10.6%），滤泡性肿瘤3个（0.4%），可疑恶性结节91个（12.1%），恶性结节158个（20.9%），标本满意率为89.3%（674/755）。≤10 mm与>10 mm甲状腺结节标本不满意率、AUS病变率、恶性结节率比较，差异均无统计学意义（P>0.05）。≤5 mm与>5 mm甲状腺结节标本不满意率、AUS病变率比较，差异无统计学意义（P>0.05）；≤5 mm甲状腺结节恶性结节率低于>5 mm甲状腺结节（P<0.001）。在202个获得手术病理结果的结节中，FNA能确定诊断的结节为173个，FNA诊断甲状腺结节的灵敏度、特异度、准确性、阳性预测值及阴性预测值分别为94.3%（150/159）、85.7%（12/14）、93.6%（162/173）、98.7%（150/152）和57.1%（12/21）。结论　超声引导下甲状腺FNA鉴别甲状腺良恶性结节具有重要价值，尤其具有非常高的阳性预测值；结节大小对Bethesda细胞病理学分类无明显影响，标本满意率受熟练程度影响。

关键词: 甲状腺结节；Bethesda病理分级；超声检查；活组织检查, 细针