The role of multimodal ultrasonography evaluation in thyroid nodule characterization and retrospective comparison of histopathology results

Differential diagnosis of benign and malignant thyroid nodules can be difficult using conventional ultrasound (US). This study aimed to evaluate whether multimodal ultrasound imaging can improve differentiation and characterization of benign and malignant thyroid nodules. Thyroid nodules assessed by grey scale US and fine needle aspiration biopsy were evaluated retrospectively. Study was conducted with 81 thyroid nodules in 77 patients with vascular index findings assessed by superb microvascular imaging (SMI), and elastisity assessed by shear wave elastography (SWE). The pathology results of 81 thyroid nodules were 15 malignant thyroid nodules and 66 benign nodules. Gray-scale US features of hypoechogenicity, solid component, poorly defined margin, a shape that is taller than wide, and SWE features of low elasticity were more significantly seen in malignant nodules than benign nodules. In the ROC analysis, it was observed that the best cut-off value for the vascular index evaluated by SMI was above 9.2% (AUC=0.637, sensitivity 60%, specificity 96.6%), and for the elasticity evaluated by SWE was above 43,9 kPa (AUC=0.671, sensitivity 60%, specificity 72.7%) in the diagnosis of malignant thyroid nodules. The specifity of the combination of the three US methods was significantly higher than that of each of the three methods separately. The sensitivity and specificity of multimodal US were 6.6-40% and 98.4-100%, respectively. The results of this study suggest that the application of multimodal US, including grey scale, SMI and SWE, may help rule out the diagnosis of malign thyroid nodules.