The Value of Elasticity Contrast Index in the Differential Diagnosis of Thyroid Solid Nodules

To assess the clinical value of elasticity contrast index (ECI) in differentiating malignant thyroid nodules from benign ones.

Conventional ultrasound and elastography with pulsation of the carotid artery used as the compression source were retrospectively reviewed on 175 patients (143 females and 32 males; mean ± SD age, 45.17 ± 11.45 years) with 236 solid nodules (113 malignant and 123 benign). All nodules were confirmed by fine-needle aspiration or surgery to be accurately diagnosed. Elasticity contrast index values were computed and used to quantify local stiffness contrast within a nodule as determined with elastography. Elasticity contrast index values between the malignant and benign groups were compared and then related with pathological results. Diagnostic performance of this method was evaluated with use of the receiver operating characteristic curve.

Mean ± SD ECI values for malignant thyroid nodules were significantly greater than those for benign nodules (3.67 ± 1.20 vs 1.80 ± 0.74, P < 0.01). Area under the receiver operating characteristic curve of ECI values was 0.907 (95% confidence interval, 0.867-0.948), and the best cutoff point was 2.16, leading to a sensitivity of 90.3%, specificity of 82.9%, positive predictive value of 83.7% and negative predictive value of 91.2%.

Elasticity contrast index values can serve as a useful parameter in the differential diagnosis of solid thyroid nodules. With the use of ECI values, objective quantitative information on the tumor stiffness can be achieved to improve diagnostic confidence.