To investigate the value of 2020 Chinese guidelines for ultrasound malignancy risk stratification of thyroid nodules (C-TIRADS) in the ultrasonic diagnosis of benign and malignant thyroid nodules in elderly patients.

Two hundred and twenty-five elderly patients with 359 thyroid nodules treated in the Xiangzhou District People's Hospital and the Fifth Affiliated Hospital of Sun Yat-sen University from January 2020 to October 2022 were retrospectively selected. The ultrasound features of all the thyroid nodules were collected, and all the nodules were categorized based on C-TIRADS and 2017 American College of Radiology Thyroid Imaging Reporting and Data System (ACR-TIRADS). The diagnostic efficacy of C-TIRADS was analyzed by comparing with ACR-TIRADS based on the pathological results as the gold standard. T test or Nonparametric test was used for comparison of measurement data, χ² test was used for comparison of counting data. The receiver operating characteristic curve (ROC) was used to analyze the diagnostic efficiency of C-TIRADS.

Among 359 thyroid nodules, 227 were benign (63.23%) and 132 were malignant (36.77%) by postoperative pathology. The maximum diameter of malignant nodules was significantly smaller than that of benign nodules (t=6.730, P < 0.01). The thyroid nodules had a higher rate of malignancy with more ultrasound features including solid, markedly hypoechoic, ill-defined margin or extrathyroid extension, vertical orientation and microcalcification. The optimal truncation value of C-TIRADS in differentiating benign and malignant nodule was class 4B, and the specificity, positive predictive value and area under the ROC were higher than those of ACR-TIRADS (χ²=11.836 and 5.222, Z=3.694, P < 0.05 or P < 0.01).

C-TIRADS has good diagnostic efficiency of thyroid nodules, which can reduce unnecessary thyroid nodule puncture biopsy or surgical treatment, and is helpful to simplify the ultrasound evaluation process and improve work efficiency.