Objective: To evaluate the accuracy of elastography alone and a combination of elastography and Siriraj thyroid imaging reporting and data system (TIRADS) in predicting malignant risk of thyroid nodule.

Materials and Methods: Between June 2011 and May 2013, 114 thyroid nodules in 112 patients that underwent ultrasound (US), guided nodule’s biopsy with US elastography, and had available pathologic results were included. Tissue stiffness on US elastography was retrospectively scored using the Ueno and Ito score, and grey scale ultrasonography was scored using the Siriraj TIRADS. Sensitivity and specificity were calculated for both US elastography alone and combination of US elastography and TIRADS.

Results: On the US elastography, 12 cases had a score of 1 and were all benign lesions, 53 cases had a score of 2 in which there was one malignant and 52 benign lesions, 40 cases had a score of 3 in which there was 4 malignant lesions and 36 benign lesions, eight cases had a score of 4 in which there was seven malignant lesions and one benign lesion. There was no lesion with a score of 5. Sensitivity and specificity of the US elastography were 58.3% and 99%, respectively. Sensitivity and specificity of combination of the US elastography and the Siriraj TIRADS were 58.3% and 100%, respectively.

Conclusion: The US elastography is a potential additional tool in diagnosis of malignant thyroid nodule with high specificity and high accuracy, especially when combined with the Siriraj TIRADS score that is used in cancer screening.

Keywords: Elastography, Siriraj TIRADS, Thyroid nodule malignancy

Received 29 Jan 2018 | Revised 9 May 2018 | Accepted 15 May 2018