Abstract:

Objective To explore the diagnostic value of ultrasound-guided fine-needle aspiration biopsy (US-FNAB) for thyroid imaging reporting and data system (TI-RADS) 4 class thyroid nodules. Methods The preoperative ultrasound features of patients with thyroid nodule who received US-FNAB examination in Ruijin Hospital of Shanghai Jiao Tong University School of Medicine were retrospectively analyzed. The malignant risk of each nodule was evaluated and classified according to TI-RADS. A total of 281 TI-RADS 4a, TI-RADS 4b, and TI-RADS 4c class thyroid nodules of 265 patients were classified as suspicious nodules and received US-FNAB examination. The US-FNAB cytological diagnosis results, pathological results, or follow-up findings of 274 nodules were compared and studied after eliminating patients whose diagnostic results were irrelevant to cytology. Results Among 281 TI-RADS 4 class thyroid nodules diagnosed by the cytology, 97 nodules were malignant; 45 nodules were suspicious of malignancy; 120 nodules were benign; 7 nodules were unsatisfactory; and 12 nodules were undetermined. According to postoperative pathological results or clinical follow-ups, 146 nodules were malignant and 128 nodules were benign. The difference of US-FNAB cytological diagnosis results and actual results was statistically significant (P<0.001). The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of US-FNAB cytological diagnosis of TI-RADS 4 class thyroid nodules were 93.83%, 96.09%, 96.48%, 93.18%, and 94.89%, respectively. Conclusion US-FNAB examination is valuable for the diagnosis of TI-RADS 4 class thyroid nodules and can effectively improves the accuracy of preoperative diagnosis. TI-RADS classification is helpful for choosing clinical treatments of suspicious thyroid nodules.

Key words: TI-RADS 4 class thyroid nodule, fine-needle aspiration biopsy, diagnostic value