Objective:

To investigate the ultrasonographic characteristics of thyroid nodules with false negative results of ultrasound-guided fine-needle aspiration cytology (FNAC).

Methods:

A total of 310 patients with negative results who underwent FNAC from January 2017 to May 2019 were enrolled. 88 patients confirmed by pathology were included in this study. Ultrasound features included position

the maximum diameter

A/T

echo leve

l

margin

halo

posterior acoustic attenuation

internal cystic changes

calcification and blood supply. The above indicators were compared with pathology results. The patients were divided into two groups: false negative and true negative groups. Single factor analysis and logistic regression analysis were used to evaluate the correlation between false negative results of FNAC and ultrasonographic characteristics of thyroid nodules.

Results:

A total of 88 cases with the false negative proportion was including 24 cases of papillary thyroid carcinoma

1 case of follicular thyroid carcinoma. Single factor analysis showed that false-negative results were increased in the nodes with A/T＞1

non-hypoechoic

irregular margin

internal cystic changes

calcification and increased blood supply

the difference between the two groups was statistically significant compared with the true negative group (

P

＜0.05). However

the maximum diameter

position

halo and posterior acoustic attenuation were not associated with the false negative results (

P

＞0.05). Logistic regression analysis showed that A/T＞1

calcification

and high blood supply were associated with the false negative results of FNAC.

Conclusion:

When thyroid nodules with sonographic characteristics such as aspect ratio＞1

calcification and rich blood supply were prone to false-negative results during FNAC.