Can real-time ultrasound elastography using the color score and strain ratio differentiate between benign and malignant solitary thyroid nodules?

Abstract

Background: Solitary thyroid nodule may represent a multitude of thyroid disorders; therefore, detection of whether these nodules are benign or malignant is crucial for patient’s triage. Objective: To evaluate the diagnostic performance of the latest generation of real-time ultrasound elastography (USE) in differentiation between benign and malignant solitary thyroid nodules. Materials and methods: Thirty consecutive patients who were referred for surgical treatment were prospectively examined by real-time USE. Tissue stiffness on real-time USE was determined with light compression using the standard elastography color scoring system according to Rago criteria ranging from 1 (low stiffness over the entire nodule) to 5 (high stiffness over the entire nodule and surrounding tissue). The strain ratio (normal tissue to lesion strain ratio) was calculated. The histopathological examination of these resected nodules was used as the diagnostic standard of reference. Results: Scores of 1 and 2 with Rago criteria were highly significant seen in benign nodules, whereas, scores of 4 and 5 with Rago criteria were highly significant seen in malignant nodules (p < 0.001) with a sensitivity, specificity and diagnostic accuracy of 78.6%, 78.9% and 78.8% respectively. Additionally, the best strain ratio cut-off value for discrimination between benign and malignant nodules by using receiver operating characteristic analysis was 2.20 (area under the curve of 0.861; p value <0.001) with a consequential sensitivity, specificity and diagnostic accuracy of 85.7%, 90.5% and 88.6% respectively. Conclusion: Both the color score and the strain ratio are higher in malignant solitary thyroid nodules than those in benign ones. Consequently, real-time USE can be used for the differentiation of benign and malignant solitary thyroid nodules. Eventually, this reduces the number of superfluous surgical procedures on benign thyroid nodules.

Keywords

• Real-time ultrasound elastography (USE)
• Benign solitary thyroid nodules
• Malignant solitary thyroid nodules
• Rago criteria
• Histopathological examination