The Performance of the American Thyroid Association (ATA) and American College of Radiology (ACR-TIRAD) Thyroid Nodule Risk-Stratification Systems in Determining High-Risk Nodules, and the Correlation of Site, Size, and Autoimmunity with High-Risk Features.

Abstract

Introduction: Neck ultrasonography (US) and fine-needle aspiration (FNA) biopsy are usually used to evaluate thyroid nodules. This study aimed to evaluate the performance of two popular thyroid imaging reporting systems in detecting thyroid malignancy and to evaluate the correlation between thyroid autoimmunity, nodule site, and size in the development of malignancy.

Methods: This prospective study was conducted from January 2019 to July 2021 in Basrah, Iraq. The American Thyroid Association (ATA) and American College of Radiology-Thyroid Imaging Reporting and Data (ACR-TIRAD) systems were used to evaluate the malignant potential of 143 thyroid nodules in 131 patients.

Results: The sensitivity and positive predictive value (PPV) of the ATA system for detecting malignancy were 96% and 20.8% for low-risk and 100% and 4.3% for high-risk nodules, respectively. ACR-TIRAD sensitivity and PPV were 84% and 22.1% for low-risk and 80% and 4.2% for high-risk nodules, respectively. The specificity and negative predictive value (NPV) of the ATA system for detecting malignancy were 11.6% and 92.3% for low-risk and 10.5% and 100% for high-risk nodules, respectively. The ACR-TIRAD specificity and NPV were 28% and 87.8% for low-risk and 26% and 96.9% for high-risk nodules, respectively. The strength of the correlation between FNA performed across different Bethesda categories and age, sex, nodule size, and positive thyroid peroxidase (TPO) antibodies were 0.25, 0.01, 0.22, and 0.4, respectively.

Conclusion: Both systems are effective; however, adopting TI-RADS stratification results in fewer biopsies being performed for thyroid nodule assessment. Only sex was found to be significantly correlated with FNA performance in thyroid-nodule evaluation.