Value of Thyroid Imaging Reporting and Data System in Initial Bethesda Category III Thyroid Nodules

Background. To evaluate the role of Thyroid Imaging Reporting and Data System (TI-RADS) in predicting malignancy for cytological Bethesda system III nodules. Method. The study included 188 thyroid nodules with first Bethesda system III cytology on surgery or repeat FNA. Patients' clinicopathologic parameters and ultrasonographic (US) nodule characteristics were evaluated according to benignity and malignancy. Using the TI-RADS classification system, thyroid nodules were categorized. Results. The size of malignant nodules was significantly lower than that of benign nodules (P < 0.001). Thyroid nodules associated with concomitant thyroid carcinoma had a significantly increased risk of malignancy (P < 0.001). Univariate analysis indicated that there were significant differences in the images of benign and malignant nodules in terms of solid composition, hypoechogenicity or marked hypoechogenicity, a taller-than-wide or irregular shape, ill-defined margins, and microcalcifications presence (P < 0.05). TI-RADS categories 4c (OR = 8.3, 95% CI 3.8-18.1; P = 0.043) and 5 (OR = 9.4; 95% CI 1.2-74.2; P = 0.026) were predictive for malignancy. Conclusions. The TI-RADS US evaluation may assist the physician in deciding whether to proceed with follow-up, repeating FNA, or surgical intervention.