Role of Shear Wave Elastography in Diagnosis of Benign and Malignant Thyroid Nodules

Abstract

Introduction: The role of Virtual Touch Imaging Quantification (VTIQ), a non-invasive Shear Wave Elastography (SWE) mechanism for analysing Thyroid Nodule (TN) elasticity, in differentiating benign from malignant thyroid nodules has been little studied. Aim: To evaluate the role of VTIQ in distinguishing between benign and malignant thyroid nodules. Materials and Methods: A total of 54 selected patients with thyroid nodules who were planned for surgical treatment were included in this prospective study. Seventy-eight TNs in these patients were scanned by conventional B-mode ultrasound, colour doppler ultrasound and SWE ultrasound. Histopathological examination of the TN was also performed. Tissues stiffness was calculated by VTIQ which was used in shear wave velocity approximation. The greater the shear wave velocity means the greater the tissue stiffness measured in meter per second (m/s) and the higher the probability of malignancy. The summary Receiver Operating Characteristic curve (sROC) was used to calculate the diagnostic accuracy of SWE in diagnosing malignant nodules. Results: The surgical cytology results defined 54 (69.23%) and 24 (30.77%) thyroid nodules as malignant and benign, respectively. The ROC curve stated a single cut-off of 3.49 m/s of a Shear Wave Velocity (SWV) for predicting the diagnostic accuracy of the Thyroid Cancer (TC). The diagnostic accuracy was 62.96%; the Positive Predictive Values (PPV) for malignant and benign tumours was 95.12%, and 59.46%, respectively. Compared to B-mode ultrasound features for predicting the diagnostic accuracy of the thyroid cancer, SWV ≥3.49 m/s indicates a higher diagnostic accuracy of the thyroid cancer in this study (p<0.0001). Conclusion: The Shear Wave Elastography (SWE) has a high diagnostic accuracy in the diagnosis of malignant and benign thyroid nodules of diameter more than 1 cm and can be used as a standard diagnostic tool for distinguishing between benign and malignant thyroid nodules.

Keywords

• shear wave velocity
• thyroid cancer
• ultrasound
• virtual touch imaging quantification