分析影响甲状腺结节弹性应变率比值（SR）的相关因素，探讨SR在甲状腺结节良恶性鉴别诊断中的应用价值及其应用策略。

选择2012年1月至2014年2月南京大学医学院附属鼓楼医院收治的甲状腺结节患者468例，共476个结节。测量甲状腺结节的SR。绘制SR鉴别诊断甲状腺结节良恶性的操作者工作特征（ROC）曲线；采用Pearson双变量相关法分析甲状腺结节大小、内部回声、钙化、血流与SR及病理结果的相关性。

ROC曲线显示，SR=0.5为SR鉴别诊断甲状腺结节良恶性的最佳阈值，诊断敏感度为84.8%，特异度为85.9%，曲线下面积为0.894。SR与甲状腺结节大小、回声、钙化、血流及良恶性均有相关性（r=0.158，P=0.001；r=-0.209，P=0.000；r=-0.218，P=0.000；r=0.189，P=0.000；r=-0.519，P=0.000）。甲状腺结节良恶性与结节大小、血流均无相关性（r=-0.025，P=0.582；r=-0.070，P=0.126），与回声、钙化、患者年龄、SR有相关性（r=0.265，P=0.000；r=0.185，P=0.000；r=-0.207，P=0.000；r=-0.519，P=0.000）。

甲状腺结节良恶性的鉴别诊断需在二维超声基础上联合SR测定和细针穿刺活检才能提高诊断准确率。

To study the application of strain ratio in differentiation of benign and malignant thyroid nodules through analyzing the influencing factors of the elastic strain ratio (SR) of thyroid nodules.

There were 468 patients with 476 thyroid nodules in present study, who came from the Nanjing Drum Tower Hospital from January 2012 to February 2014. SR characteristics of thyroid nodules were retrospectively analyzed, and the critical values were found by receiver-operating characteristic (ROC) curve. Then the size, echo, calcification, blood flow and the correlation between SR and pathology were analyzed by Pearson bivariate correlation analysis.

The ROC curve showed that SR=0.5 was the best threshold value of SR in differential diagnosis of benign and malignant thyroid nodules. The diagnostic sensitivity, specificity, and the area under the curve were 84.8%, 85.9%, and 0.894, respectively. SR was negatively correlated with echo and calcification, while positively correlated with nodule size and blood flow (r=0.158, P=0.001; r=-0.209, P=0.000; r=-0.218, P=0.000; r=0.189, P=0.000; r=-0.519, P=0.000). The pathology of thyroid nodules had no correlation with nodule size and blood flow (r=-0.025, P=0.582; r=-0.070, P=0.126). The pathology was positively correlated with echo and calcification, while negatively correlated with age (r=0.265, P=0.000; r=0.185, P=0.000; r=-0.207, P=0.000; r=-0.519, P=0.000).

To improve the accuracy of diagnosis, the differential diagnosis of benign and malignant thyroid nodules should be based on two-dimensional ultrasound combined with SR and fine needle aspiration.