Comparison of diagnostic performance and FNA management of the ACR-TIRADS and Chinese-TIRADS based on surgical histological evidence

BACKGROUND: The sonography-based risk stratification of thyroid nodules is based on the different sonographic features of benign and malignant thyroid nodules. The American College of Radiology (ACR) Thyroid Imaging Reporting and Data System (TIRADS) and the Chinese-TIRADS define different risks for malignancy categories and the size criteria for fine-needle aspiration (FNA). Few studies have compared their diagnostic performance and FNA management approaches. Thus, we sought to compare the diagnostic performance and FNA management approaches of the ACR-TIRADS and Chinese-TIRADS based on surgical histological evidence. METHODS: This retrospective study included patients with complete thyroid ultrasound images and histologic evidence who were consecutively selected from The Affiliated Hospital of Nanjing University of Chinese Medicine. A total of 333 nodules from 252 patients with definitive surgical histological findings were examined. Ultrasonography categories and FNA management proposals were assigned according to the ACR-TIRADS and Chinese-TIRADS. The thyroid nodules were divided into 2 groups based on a cut-off size of 1 cm. The diagnostic performance and recommended and unnecessary FNA rates for each group were compared for both systems. RESULTS: Overall, 280 malignant thyroid nodules (84.1%) and 53 benign nodules (15.9%) were analyzed. Across all groups, the ACR-TIRADS had higher sensitivity, specificity, positive and negative predictive values, and accuracy, and a higher area under the curve (AUC) than the Chinese-TIRADS. However, there was a significant difference in the negative predictive value between the ACR-TIRADS and Chinese-TIRADS of <1 and ≥1 cm, and the overall AUCs differed significantly (39.5% vs. 35.1%, P=0.007 for <1 cm; 70.0% vs. 62.8%, P=0.014 for ≥1 cm; 0.843 vs. 0.806, P=0.037 for all). The rate for recommending the FNA of the nodules in the ACR-TIRADS was lower than that in the Chinese-TIRADS (25.2% vs. 56.5%, P<0.0001), but there was no significant difference between the ACR-TIRADS and Chinese-TIRADS in terms of the unnecessary FNA rate (14.3% vs. 13.8%, P=0.931). The kappa statistics for the consistency of the ACR-TIRADS and Chinese-TIRADS FNA recommendations for nodules sized ≥1.0 to <1.5, ≥1.5 to <2.5, and ≥2.5 cm were 0.084, 0.635, and 0.909, respectively. CONCLUSIONS: The ACR-TIRADS had slightly better diagnostic performance and a lower recommended FNA rate than the Chinese-TIRADS for thyroid nodules. For thyroid nodules ≥1.5 cm in size, the FNA recommendations of the 2 guidelines had good consistency.