Imaging characteristics of acoustic radiation force impulse elastography for thyroid nodules

Objectives: To investigate the acoustic radiation force impulse (ARFI) imaging characteristics of thyroid nodules. The ARFI technology consisted of virtual touch tissue imaging (VTI) and virtual touch tissue quantification (VTQ). Methods: One hundred thyroid nodules (80 benign, 20 malignant) in 76 patients were retrospectively analysed. The VTI images of thyroid nodules were classified into 6-point levels. The shear wave velocities (SWVs) of thyroid nodules were measured by VTQ measurements. All thyroid nodules were examined pathologically after surgery and the pathological results were correlated with VTI levels and VTQ values. Results: VTI levels and VTQ values of malignant nodules were higher than those of benign nodules (both p<;0.001). With the VTI cut-off level of 4, the sensitivity, specificity and accuracy for differentiating between benign and malignant nodules were 55.0%, 92.5% and 85.0%, respectively. When using the VTQ cut-off value of 2.49m/s, the sensitivity, specificity and accuracy in differential diagnosis of thyroid nodules were 80.0%, 85.0% and 84.0%, respectively. Conclusions: The stiffness of thyroid nodules could be qualitatively or quantitatively evaluated by VTI and VTQ, which might provide grounds for the diagnosis of thyroid nodules.