Abstract

ntroduction: This paper evaluated the diagnostic performance of shear wave elastography (SWE) alone and in combination with the Thyroid Imaging Reporting and Data System (TI-RADS) with the end of improving the distinction between benign or malignant thyroid nodules.
Methodology: 55 nodules were estimated in 50 patients (36 females and 19 males, with a mean age of 51.98±9.98) by conventional ultrasound and SWE. Size, echogenicity, margin, calcification, composition, shape, and color Doppler were reviewed separately in each nodule. Elasticity was assessed qualitatively by examining color maps and was quantitatively measured by appraising velocity in Region of Interest (ROI) in the stiffest areas and eventually the maximum and mean velocity were achieved. The ROC curve was analyzed in order to specify the best cut-off point of SWV (Shear Wave Velocity).
 Results: Among the B-mode and color Doppler features, shape features (p<0.001), Halo (p=0.001), Doppler grade (p<0.001), and among the SWE features, grade II color map (p=0.001), grade IV color map (p<0.001), grade V color map (p=0.024), maximum velocity (p<0.001) and mean velocity (p<0.001) were significantly and statistically associated with malignancy. According to Nagelkerke R2, it was demonstrated in statistical analysis that the maximum velocity was designated as the strongest predictor of malignancy. The area under the Curve (AUC) for maximum SWE was considered to be 0.854 (0.969-0.749 confidence interval, (p<0.001)). The best cut-off point for maximum and mean velocity for differentiating between benign and malignant nodules was 3.61 m/s (sensitivity was 87.5% and specificity was 79.49%) and 3.44 m/s, respectively. 
Conclusion: SWE was an encouraging test for estimating preoperative malignancy risk in suspected patients with TIRADS 4 category of thyroid nodules. The maximum velocity had the strongest prediction of malignancy among conventional and elastographic ultrasound variables