Diagnostic Accuracy of Thyroid Cancer Using the American Thyroid Association Guidelines and American College of Radiology-Thyroid Imaging Reporting and Data System

Objective: To compare the American Thyroid Association (ATA) classification system of 2015 with the American College of Radiology (ACR) Thyroid Imaging Reporting and Data System (TI-RADS) of 2017 to determine the superior system to predict cancer risk in thyroid nodules. Materials and Methods: The present study was a retrospective study that included patients with thyroid nodule(s) referred to the department of radiology for fine-needle aspiration (FNA) between February 2019 and March 2021. The authors assessed the ability of either system to predict malignancy based on FNA cytology results. Sensitivity, specificity, negative predictive values (NPV), and positive predictive values (PPV) were calculated. Results: One hundred sixty-five nodules were reviewed based on the ATA guideline of 2015 and ACR-TI-RADS of 2017. The sensitivity, specificity, PPV, and NPV of the ATA guidelines were 95.45%, 65.04%, 29.58%, and 98.94%, respectively, while that of the ACR-TI-RADS were 95.45%, 62.24%, 28%, and 98.89%, respectively. Conclusion: The ATA guidelines of 2015 and the ACR-TI-RADS of 2017 have comparable sensitivity and NPV for thyroid carcinoma diagnosis with moderate specificity for both systems. These results confirm a high probability of both systems rejecting malignancy. Keywords: Thyroid; FNA; ATA guideline; ACR-TI-RADs