Abstract: Objective To study the value of ROI A value in the strain ratio and the elasticity scores by the 4-score system in
ultrasonic elastography in differential diagnosis of benign and malignant thyroid nodules. Methods A total of 124 patients
with 166 thyroid nodules underwent examinations with real-time ultrasonic elastography to obtain the elasticity score and the
ROI A value in strain ratio. Receiver operating characteristic (ROC) curves were used to assess the diagnostic value of ROI A
value, and the best cutoff point was determined. The results of diagnosis based on ROI A value, elasticity scores, and their
combination were compared with the results of pathological diagnosis. Results The area under the ROC curve (Az) of ROI A
value for differentiating benign and malignant thyroid nodules was 0.825. The best diagnostic cut-off point of ROI A value was
0.00165. In differentiating benign and malignant thyroid nodules, the sensitivity, specificity, accuracy and odds ratio were
82.93%, 72.80%, 75.30%, and 13.0 for ROI A value, 87.80%, 80.00%, 81.93%, and 28.8 for the elasticity scores, and 73.17%,
91.20%, 86.75%, and 32.1 for their combination, respectively. The odds ratio of the combined diagnosis was the highest, and the
accuracy of the combined diagnosis was significantly higher than that of ROI A value (χ2=19.31, P<0.05) and the elasticity
scores (χ2=12.03, P<0.05). Conclusion ROI A value has moderate diagnostic value and clinical practicability in differentiating
thyroid nodules. The diagnostic accuracy of ROI Avalue can be improved by combining with the elasticity scores.