Prospective evaluation of semiquantitative strain ratio and quantitative 2D ultrasound shear wave elastography (SWE) in association with TIRADS classification for thyroid nodule characterization

PURPOSE:  To evaluate the diagnostic performance of strain ratio elastography (SRE) and shear wave elastography (SWE) alone and in combination with Thyroid Imaging Reporting and Data System (TIRADS) classification parameters to improve differentiation between benign and malignant thyroid nodules. MATERIALS AND METHODS:  In this prospective study benign (n = 191) and malignant (n = 52) thyroid nodules were examined with high-resolution ultrasound (US) features using the TIRADS lexicon and SRE semiquantitative and SWE quantitative findings using histology or cytology as the gold standard with a 12-month follow-up. Sensitivity (Se), specificity (Sp) and the area under the ROC curve (AUROC) were used to evaluate the diagnostic performance of each feature and combinations of the methods. RESULTS:  TIRADS score showed a sensitivity of 59.6 %, a specificity of 83.8 % with an AUROC of 0.717, a PPV of 50.0 % and an NPV of 88.4 %. SRE yielded the highest performance with a sensitivity of 82.7 %, a specificity of 92.7 % with AUROC of 0.877, a PPV 75.4 % and an NPV of 95.2 %. SWE (kPa) had a sensitivity and specificity of 67.3 % and 82.7 %, respectively, with an AUROC of 0.750, a PPV of 51.5 % and an NPV of 90.3 %. Differences were significant for SRE only but not for SWE. CONCLUSION:  Ultrasound elastography may improve thyroid nodule discrimination. In particular, SRE has a better performance than TIRADS classification, while their combination improves sensitivity.