The values of shear wave elastography in avoiding repeat fine-needle aspiration for thyroid nodules with nondiagnostic and undetermined cytology.

ABSTRACT

OBJECTIVE: To evaluate the value of shear wave elastography (SWE) in avoiding repeat fine-needle aspiration of thyroid nodules with nondiagnostic and undetermined cytology. METHODS: A total of 232 thyroid nodules with nondiagnostic (n = 132) and undetermined (n = 100) cytology underwent ultrasound (US) and SWE, followed by repeat ultrasound (US)-guided fine-needle aspiration cytology (FNAC). The final diagnosis was based on cytological or pathological findings. The US and SWE characteristics of benign and malignant nodules were compared using the χ2 -test. The receiver operating characteristic (ROC) curves of the thyroid imaging reporting and data system (TI-RADS) categories from the US and the EMean and ESD from the SWE were graphed, and the areas under the curves (AUCs) were compared using a Z test. RESULTS: There were significant differences between the benign and malignant nodules in terms of the echogenicity, shape, margin, calcification and TI-RADS categories (all P < 0.05). The differences were significant between the malignant and benign nodules for EMean [(34.57 ± 14.81) kPa vs. (19.18 ± 7.09) kPa] and ESD [(13.68 ± 13.01) kPa vs. (3.97 ± 2.58) kPa] (both P < 0.001). Though the difference in the AUCs of EMean (0.864) and ESD (0.876) was not significant (P = 0.745), they both had higher diagnostic performances in comparison with TI-RADS categories (0.762) (all P < 0.05). Moreover, ESD attained a sensitivity of 100% with a relatively higher specificity of 49.75% when its cut-off value was 3.3 kPa. CONCLUSIONS: Shear wave elastography is a promising imaging method for reducing repeat FNAC for benign thyroid nodules with nondiagnostic and undetermined cytology when using ESD as an index.