目的 探讨超微血管成像技术（Superb Microvascular Imaging，SMI）评估甲状腺结节内 血管直径在鉴别良恶性结节中的应用价值。方法 随机选取超声检出的甲状腺结节105例患者111 个病灶，根据其病理结果分成良性组和恶性组，再根据结节的大小将良性组、恶性组分别分为 ≤2 cm组和>2 cm组，应用SMI软件检测结节内血管直径，比较测量结果。结果 结节≤2 cm中良 性组、恶性组平均血管直径分别为（0.90±0.13）、（0.61±0.17）mm，两组比较差异有统计学 意义（P=0.000），其诊断阈为≤0.75 mm，敏感度为77%，特异度为85%；结节>2 cm组中良性 组、恶性组平均血管直径分别为（1.12±0.19）、（0.76±0.20）mm，两组比较差异有统计学意义 （P=0.000），其诊断阈为≤0.95 mm，敏感度为76%，特异度为83%。结论 SMI技术能有效测量 血管直径，有利于甲状腺良恶性结节的鉴别诊断。

Objective To investigate the application value of vascular caliber in identifying the benign and malignant thyroid nodules by superb microvascular imaging (SMI) technology. Methods Totally 105 patients with 111 thyroid nodules were randomly selected by ultrasonography, which were divided into benign group and maligant group according to pathological detection results. Then benign group and maligant group were divided into two groups respectively according to the size of the nodules, and the grouped criterion was 2 cm. SMI software was used to measure the blood vessel diameters in the thyroid nodules, and compared the results. Results In the group which the value of vascular caliber was less than or equal to 2 cm, the average blood vessel diameters of benign group and maligant group were separately (0.90±0.13), (0.61±0.17) mm, so there were significant statistical differences between the two groups (P=0.000), the diagnostic threshold was 0.75 mm, the sensitivity was 77%, the specificity was 85%. In the group which the value of vascular caliber was larger than 2 cm, the corresponding values were separately (1.12±0.19), (0.76±0.20) mm, there were also significant statistical differences between two groups (P=0.000), the diagnostic threshold was 0.95 mm, the sensitivity was 76%, the specificity was 83%. Conclusion SMI can effectively measure the diameter of blood vessels, which is conducive to diagnose the benign and malignant thyroid nodules.