Value of color Doppler ultrasound, ultrasound-guided fine needle aspiration cytology combined with BRAF^V600E gene detection in diagnosis of microthyroid nodules

Objective To investigate the diagnostic value of color Doppler ultrasound, ultrasound-guided fine needle aspiration cytology (US-FNAC) combined with BRAF^V600E gene detection in small thyroid nodules.

Methods A total of 103 patients with moderate or high risk small thyroid nodules were selected as study subjects. The Thyroid Imaging Reporting and Data System (TI-RADS) grading, preoperative color doppler ultrasound US-FNAC and silk/threonine specific kinase mutant gene V600E (BRAF^V600E) detection were performed. The sensitivity, specificity and accuracy of each examination alone and their combination were compared according to the pathological results, and the diagnostic performance was analyzed.

Results The ultrasound examination showed that there were statistically significant differences in aspect ratio, structure, echo, echoes, calcification and marginal growth of nodules of different nature (P < 0.05). Of the 103 subjects, 63 cases (98 nodules with 67 malignant ones) were diagnosed as grade V or VI by US-FNAC examination, accounting for 61.2%. There were 26 patients with grade Ⅲ and Ⅳ (32 nodules with 14 malignant ones), accounting for 25.2%. There were 12 cases of grade Ⅱ (12 nodules in total without malignancy), accounting for 11.7%; there were 2 cases of grade Ⅰ (2 nodules with one malignant nodule), accounting for 1.9%. BRAF^V600E gene examination showed that 72 cases (111 nodules, 76 of which were malignant) was detected, accounting for 69.9%. There were 31 patients without mutation (33 nodules in total, 6 of which were malignant), accounting for 30.1%. The sensitivity, specificity and accuracy of ultrasound examination, US-FNAC examination and BRAF^V600E gene test were 75.3%, 62.5%, 73.0%, respectively, 79.5%, 68.8%, 77.5%, respectively and 93.2%, 68.8%, 88.8%, respectively. The sensitivity, specificity and accuracy of their combined diagnosis were the highest, which were 97.3%, 75.0% and 93.3%, respectively. The sensitivity, specificity and accuracy of their combined diagnosis were higher than those of single detection (P < 0.05).

Conclusion Combined detection can improve the detection rate of thyroid papillary microcarcinoma, which is conducive to accurate preoperative evaluation of small nodules.