Diagnostic value of ultrasound-guided fine-needle aspiration cytology in the pathological natures of thyroid nodules: A retrospective study.

Objective: Thyroid nodules, a clinical disease with high incidence, include benign and malignant types. This study aims to evaluate the diagnostic value of ultrasound-guided fine-needle aspiration cytology (US-FNAC) in determining the pathological nature of thyroid nodules and to conduct an in-depth analysis of its diagnostic efficacy across nodules of varying sizes.

Material and methods: This retrospective study identified 116 patients undergoing thyroidectomy in Zibo Central hospital from January 2022 to March 2023, with 98 meeting the study's inclusion criteria. All patients received ultrasound and US-FNAC examinations before surgery to analyze the ultrasonic features of thyroid nodules. The diagnosis results of pathological natures obtained by US-FNAC were analyzed with the result of post-operative pathological examination as the gold standard. The patients were divided into four groups according to the median and quartile of nodular diameters to explore the diagnostic efficacy of US-FNAC for the pathological natures of thyroid nodules with various diameters and comprehensively evaluate its application value. The evaluation tool of diagnostic efficacy was the receiver operator characteristic (ROC) curve.

Results: A total of 98 puncture nodules were evaluated, with a diameter of 0.8-5.2 cm. Post-operative pathological examination showed 10 (10.20%) benign and 88 (89.80%) malignant lesions. The ultrasound examination showed 14 (14.29%) benign and 84 (85.71%) suspected malignant lesions. The US-FNAC results showed 2 cases (2.04%) of type I, 9 cases (9.18%) of type II, 3 cases (3.06%) of type III, 29 cases (29.59%) of type IV, 39 cases (39.80%) of type V, and 16 cases (16.33%) of type VI, including 9 (9.18%) benign and 84 (85.72%) malignant lesions and 5 (5.10%) uncertain pathological natures. According to the median and quartile of nodular diameters, specifically, 1.90 (1.60, 2.30) cm, 93 nodules with decided pathological natures were divided into groups Q1 (n = 24, ≤1.6 cm), Q2 (n = 26, 1.7-1.9 cm), Q3 (n = 24, 2.0-2.3 cm), and Q4 (n = 19, >2.3 cm). The results of ROC analysis showed that the area under the curve (AUC), sensitivity, and specificity of US-FNAC diagnosis were 0.894, 98.80%, and 80.00%, respectively. The AUCs of US-FNAC in groups Q1, Q2, Q3, and Q4 were 0.978, 1.000, 0.977, and 0.971. The AUCs of Q1 group, Q2 group, Q3 group and Q4 group were all > 0.9, and US-FNAC had high diagnostic efficiency for the pathological properties of thyroid nodules with different diameters.

Conclusion: US-FNAC has a high diagnostic efficiency for the pathological properties of thyroid nodules. Whether the nodule diameter has an effect on the accuracy of this method requires more clinical evidence.