Diagnostic Value Of Us-guided Fine-needle Aspiration Cytology For TI-RADS 4 Class Thyroid Nodules

Objective:To explore the diagnostic value of ultrasound-guided fine-needle aspiration cytology(US-FNAC) for TI-RADS 4 class thyroid nodules. Method:A retrospective analysis was made on the clinical date of a total of 206 patients with 218 TI-RADS 4 class thyroid nodules who underwent ultrasound-guided fine-needle aspiration cytology in the First Hospital of Jilin University. According to malignancy risk of TI-RADS classification criteria for assessing noudules, TI-RADS 4a,TI-RADS 4b,and TI-RADS 4c class thyroid nodules were classified as suspicious malignant noudules. Excluding drawn cases can not be diagnosed or unsatisfactory,all nodules underwent US-FNAC and surgical treatment.The US-FNAC results of all nodules were compared with the pathological results after surgery. Results:(1).Among 218 TI-RADS 4 class thyroid nodules diagnosed by US-FNAC results,71 nodules were negative,and 147 noudules were positive.According to the the pathological results after surgery,75 nodules were benign and 143 nodules were malignant.Among the postoperative pathological results of group I, 40 nodules were benign and 10 nodules were malignant. Among the postoperative pathological results of group II, 27 nodules were benign and 65 nodules were malignant. Among the postoperative pathological results of group III, 8 nodules were benign and 68 nodules were malignant.(2) Among the US-FNAC results in this study,8 cases were false positive and 4 cases were false negative.3 cases were nodular goiter,2 cases were adenomatous goiter,and 3 cases were follicular adenoma in the false positive cases.And in the false negative cases,3 nodules were papillary carcinoma and one case was follicular carcinoma.(3)In this study,the actual rate of malignancy of TI-RADS 4a,TI-RADS 4b,and TI-RADS 4c class thyroid nodules were 20%(10/50), 70.65%(65/92) and 89.47%(68/76).(4)The sensitivity, specificity, accuracy, positive predictive value and negative predictive value of US-FNAC diagnosis for TI-RADS 4a class thyroid nodules were 80.00%(8/10),95.00%(38/40),92.00%(46/50),80.00%(8/10),95.00%(38/40),resectively. The sensitivity, specificity, accuracy, positive predictive value and negative predictive value of US-FNAC diagnosis for TI-RADS 4b class thyroid nodules were 98.46%(64/65), 85.19%(23/27), 94.57%(87/92), 94.12%(64/68), 95.83%(23/24),resectively. The sensitivity, specificity, accuracy, positive predictive value and negative predictive value of US-FNAC diagnosis for TI-RADS 4c class thyroid nodules were 98.53%(67/68), 75.00%(6/8), 96.05%(73/76), 97.10%(67/69), 85.71%(6/7),resectively. Conclusion:(1)The preoperative US-FNAC results were highly consistent with postoperative pathological results in this study. The US-FNAC examination has a higher diagnostic value for TI-RADS 4 class thyroid nodules, and it can effectively improve the accuracy of preoperative diagnosis and guide further treatment.(2)By comparing the actual rate of malignancy of TI-RADS 4a,TI-RADS 4b,and TI-RADS 4c class thyroid nodules, we can see the actual rate of malignancy of TI-RADS 4c class thyroid nodules is highest,followed by TI-RADS 4b and TI-RADS 4a class thyroid nodules.(3)The actual rate of malignancy of TI-RADS 4a class thyroid nodules is relatively low,it may recommend shorterm follow-by to reduce unnecessary surgical trauma.(4)It is difficult to identify TI-RADS 4b class thyroid nodules by single conventional ultrasound.It can recommend to underwent preoperative US-FNAC examination for evaluation.(5) The actual rate of malignancy of TI-RADS 4c class thyroid nodules is higher,we recommend aggressive treatment,included treatment by direct operation or preoperative evaluation by US-FNAC examination.