ABSTRACT
Objective To explore the diagnostic value of ultrasound guided fine needle aspiration biopsy (US-FNAB) for thyroid imaging reported and data system (TI-RADS) 4 class ≤ 10 mm thyroid nodules.Methods The preoperative ultrasound features of patients with thyroid nodule who received USFNAB examination were retrospectively analyzed,the malignant risk of each nodule was evaluated and classified according to TI-RADS.TI-RADS 4a class thyroid nodules and diameter ≤ 10 mm of 365 patients were classified as suspicious nodules and received US-FNAB examination.The nodules were classified as ＜5 mm and 5-10 mm groups.The results of cytologic diagnosis were compared with the pathological diagnosis,and the differences for nodules with different size were analyzed.Results Among 365 TI-RADS 4 class thyroid nodules diagnosed by the cytology,68 nodules were malignant;81 nodules were suspicious of malignancy;193 nodules were benign;6 nodules were unsatisfactory;and 17 nodules were undetermined.According to postoperative pathology or follow-ups,153 nodules were malignant and 212 nodules were benign.The difference between US-FNAB results and pathology was not significant (P ＞ 0.05).Cytologic positive rate and actually malignant rate of the nodules in 5-10 mm group were higher than ＜ 5 mm groups (P ＜ 0.05).The sensitivity,specificity,positive predictive value,negative predictive value,and accuracy of US-FNAB cytological diagnosis of TI-RADS 4 class thyroid nodule were 92.2％,96.2％,94.6％,94.4％and 94.5％,respectively.Conclusion US-FNAB examination is valuable for the diagnosis of TI-RADS 4a class thyroid nodules and improves the preoperative diagnosis.