The application of strain ratio for ultrasonic elastography in diagnosis of benign and malignant thyroid nodules
超声弹性应变率值在甲状腺良恶性结节诊断中的应用

Objective To evaluate the clinical value of elasticity score and strain ratio by ultrasonography in differential diagnosis of thyroid nodules and the cut-off point of strain ratio for thyroid nodules. Methods Elasticity imaging was used to examine 64 cases of patient with 91 thyroid nodules. The elasticity scores and strain ratio were retrospectively reviewed and compared with pathology. The elasticity grades 0- II was predict of benign, grades III-IV was predict of malignant. Results （ 1 ） An elasticity score of 0- II was observed in 45 of 91 nodules in 45 cases , while a score of III-IV in the rest of 46 nodules. An elasticity score of 0- II was observed in 43 of 64 benign nodules, while a score of III-IV in 25 of 27 malignant nodules ; Elasticity score 0-II were observed in the majority of benign nodules, while score III-IV in the majority of malignant nodules. （2）67 nodules 〈 5. 525, 24 nodules ≥ 5. 525 in elastic strain ratio. The mean of elastic strain ratio of 7.38 ± 3.72 was statistically higher in 27 malignant nodules that of 2.64 ± 1.32 in 64 of benign nodules（ P 〈 0.05 ）. （3）According to ROC analysis, the cut off point of strain ratio was determined as 5. 525, Youden＇ s index was 0.78, 62 nodules with elastic strain ratio 〈 5. 525 were confirmed as benign by pathology, 22 nodules with elastic strain ratio≥5. 525 were confirmed as malignant by pathology, sensitivity was 81.5 % and specificity was 96.8%. （4）The diagnostic accuracy of the strain ratio was superior to that of elasticity score. Conclusion The strain ratio and elasticity score in elasticity images is helpful in the differential diagnosis of thyroid lesions.