Application of shear wave elastography in the management of thyroid nodules in children and adolescents: our experience and a review of the literature.

Introduction: Shear wave elastography (SWE) is an ultrasound diagnostic method used to measure tissue stiffness. Since the mechanical properties of tissue involved in the pathological process change, SWE might indicate regions of the examined tissue covered by the disease. It is well documented that SWE helps to differentiate benign and malignant nodules in thyroid glands in adults, however, there are few studies on the application of SWE in thyroid diagnosis in children. The purpose of the study was to assess the application of SWE based on Young's modulus expressed in kPa in the management of thyroid nodules in children and adolescents. Methods: In total, 116 pediatric patients (81 girls and 35 boys) with 168 thyroid nodules were enrolled in the study and qualified for SWE followed by fine needle aspiration biopsy. Results: According to the result of the cytological examination presented in the Bethesda System, nodules were classified as benign (147 nodules classified as category II according to the Bethesda System) or indeterminate or suspicious (21 nodules classified as categories III, IV, and V according to the Bethesda System). Benign cytological diagnoses were nodular goiter, parenchymal goiter, nodular colloid goiter, or lymphocytic inflammation. Among the indeterminate or suspicious nodules, 15 were diagnosed as category III according to the Bethesda System (atypia of undetermined significance (AUS) or follicular lesion of undetermined significance (FLUS) in cytology), 1 nodule was diagnosed as category IV according to the Bethesda System (suspicious for follicular neoplasm - oxyphilic cell tumor), and 5 as category V according to the Bethesda System (suspicious for malignancy). There were no significant differences in thyrotropin (TSH) and free thyroxine (fT4) concentrations between the benign and suspicious groups. Patients with benign and indeterminate or suspicious thyroid nodules were of comparable age. Mean SWE in benign nodules was statistically significantly lower than in nodules with indeterminate or suspicious cytology (42.22 ± 16.69 vs. 57.4 ± 24.0 kPa, Conclusion: Our results suggest that SWE is a viable diagnostic method, however, it still seems to need some adjustment for pediatric patients.