良恶性甲状腺小结节的超声弹性成像鉴别诊断

Ultrasonic elastography in differential diagnosis of benign and malignant small thyroid nodule

目的探讨超声弹性成像应变率比值的最佳诊断界限值，分析超声弹性成像技术在甲状腺小结节良恶性鉴别中的临床价值。方法采用HI Vision Preirus型彩色多普勒超声诊断仪对129例患者共138个直径〈1cm的甲状腺小结节进行检查，线阵探头，频率5～13MHz，分别进行常规超声、超声弹性分级及应变率比值的检查测量。所有129例：啕行组织病理学检查。绘制ROC曲线，确定应变率比值的最佳诊断界限值并分析各方法的诊断价值。结果①确定应变率比值诊断甲状腺小结节良恶性的最佳界限值为3．635，以≥3．635为恶性评价，〈3．635为良性评价；②四种诊断方法两两比较，应变率比值的特异度较常规超声联合弹性分级高，弹性分级及常规超声联合弹性分级的敏感度均较常规超声高（P〈0．05）；③分析四种方法的ROC曲线下面积，应变率比值曲线下面积〉0．9，表明有较高昀准确性，其余三种方法介于0．7～0．9，表明均有一定的准确性。结论超声弹性成像技术对甲状腺小结节良恶性的鉴别有一定的诊断价值。分级法敏感度较高，与常规超声联合应用提高了甲状腺微小癌的早期检出率。应变率比值法能够半定量反映病灶的硬度，判断甲状腺小结节的良恶性更客观，但二者均易受多种因素影响，在临床应用时需综合分析。

Objective In order to explore the best diagnostic threshold of ultrasonic elastic strain ratio and analyse the clinical value of ultrasound elastography in differential diagnosis of benign and malignant small thyroid nodules. Methods The 129 patients with small thyroid nodules （total number：138）,which were confirmed by pathology. Diameters of these nodules were less than lcm. In this study HI Vision Preirus color Doppler ultrasonic diagnostic apparatus with linear array probe was adopted. The frequency was from 5 to 13MHz. All the patients received conventional uhrasound,ultrasonic elastography for ultrasound elastography classification and strain ratio＇s measurement. All obtained data were processed by software SPSS 17.0. Using the statistical software,ROC curve was drawn. And the strain ratio＇s optimal threshold value in the differential diagnosis was obtained. The diagnostic value of the various methods were-analyzed. χ2 test was adopted to compare the differences among the various diagnostic methods. P~〈0.05 was defined as statistically significant difference. Results 1 ）The strain ratio＇s optimal threshold value was 3.635. The ratio of 3.635 or greater was malignant,while the ratio of less than 3.635 was benign; 2）Pairwi.se comparisons among the four methods of diagnosis,the strain ratio was more specific than conventional ultrasound combined with ultrasound elastography classification,the ultrasound elastography classification and conventional ultrasound combined with ultrasound elastography classification were more sensitive than conventional ultrasound,the difference had statistically significance（P〈0.05）; 3）The area under the ROC curve of four differential diagnosis methods were compared. The strain ratio of the area under the curve was greater than 0.9,showing that accuracy is high. The area under the ROC curve for the remaining three methods located at 0.7- 0.9,showing that these three methods had a certain diagnostic accuracy for small thyroid nodules. Conclusion Ultrasound elastography has certain diagnostic value for small thyroid benign and malignant nodules.The ultrasound elastography classificationcan combination with the conventional ultrasound can improve the early detection rate of thyroid microcarcinoma.The strain ratio can semi-quantitatively reflect the hardness of the lesions. It is more objective than ultrasound elastography classification in judging the benign and malignant small thyroid nodules. But they are affected by many factors ,so comprehensive judgment is required in the clinical application.