Purpose: To assess the value of Q-Elastography (Q-USE) in the characterization of thyroid nodules with indeterminate cytology (Thy3).
Materials and Methods: 312 nodules in 264 patients (185 females; 79 male patients) with Thy3 (mean age 50 years, range 18-78) were prospectively and consecutively enrolled in two specialized University Centers.
All patients underwent multiparametric CDUS and Q-USE evaluation measuring the Strain Ratio (SR). All patients underwent FNAC.
To evaluate the relationship between categorical data and final histological outcome, univariate analysis with the chi-square test and multiple logistic regression analysis was performed. Sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy were calculated. Cut-off value for strain ratio was calculated by Receiver Operating Characteristic (ROC) analysis, with Areas Under the Curve comparison with Bonferroni test. Histopathology was the gold standard.
Results: Malignant nodules were 115; while the benign were 197 (21 adenomas and 176 hyperplastic nodules).
A higher Strain Ratio in malignant nodules than benign ones was demonstrated, with an optimum SR cut-off equal to 2 obtained with ROC analysis.
Hypoechogenicity, irregular margins and SR³2.00 showed accuracy of 69%, 80% and 91%, respectively. A multivariate analysis showed a significant association between the SR and margins irregularity, thus confirming the univariate analysis findings. The diagnostic accuracy of hypoechogenicity (ROC area = 0.6725) was significantly lower than that of the strain ratio (p,0.0001) and irregular margins (p = 0.0092).
Conclusion: Q-USE could be a useful additional tool to Color-Doppler US in the differential diagnosis of thyroid nodules with indeterminate cytology.
