The value of strain ratio in differential diagnosis of thyroid solid nodules

To assess the clinical value of strain ratio in differentiating thyroid solid nodules and explore its distribution characters based on pathological results.

The study was approved by the ethic committee and the informed consents were signed. Ninety nine solid thyroid nodules (67 benign and 32 malignant) from 71 female (mean age 46.3 ± 9.8 years) and 28 male (mean age 54.9 ± 11.7 years) patients were evaluated. Five radiologists evaluated the nodules based on a four-degree elastography score system. Strain ratio was calculated on-line. Diagnostic performances of the two evaluations were compared using Receiver Operating Characteristic (ROC) curves. Values of different pathological nodules were compared by one-way ANOVA.

Areas under the ROC curve (AUC) of the five readers were 0.82, 0.81, 0.79, 0.73 and 0.83, respectively. The AUC of strain ratio evaluation was higher (0.88 vs. 0.79, p < 0.001) than that of the ES score evaluation. Best cut-off points of the two evaluations were 3.5 (82% sensitivity, 72% specificity) and 4.225 (81% sensitivity, 83% specificity), respectively. Both the ES score and strain ratio were higher for malignant nodules than that for benign ones (p < 0.001).

Strain ratio was a useful index in differential diagnosis of thyroid solid nodules. It can provide quantitative information on thyroid nodule characterization and improve diagnostic confidence. The best cut-off point for benign and malignant nodules was 4.2.