Evaluating modified ACR TI-RADS nodule size for thyroid nodules in pediatric population.

Purpose: In this study, we aimed to investigate the diagnostic performance of modified thyroid nodule size based on the American College of Radiology Thyroid Imaging Reporting and Data System (ACR TI-RADS) for the pediatric population.

Method: This retrespective study enrolled patients younger than 21 years who underwent thyroid nodule US examination between January 2021 and June 2024. Thyroid nodules were assessed according to the ACR TI-RADS and the modification of size criteria. The diagnostic performance of sensitivity, specificity, area under the receiver operating characteristic curve (AUC), unnecessary biopsy rates, and missed malignancy rates were calculated and compared.

Results: A total of 204 thyroid nodules were retrospectively included, of them 51 were confirmed malignancies. For ACR TI-RADS, the sensitivity, specificity, and AUC were 76.5% (95% CI 62.5%-87.2%), 75.2% (95% CI 67.5%-81.8%), and 0.825 (95% CI 0.756-0.894), demonstrating moderate diagnostic performance. When applied modified lower nodule size, the sensitivity was improved (82.4%, 95% CI 69.1%-91.6%, and 88.2%, 95% CI 76.1%-95.6%); however, which was at the cost of decreasing specificity (65.4%, 95% CI 57.3%-72.9% and 53.6%, 95% CI 45.4%-61.7%).

Conclusion: ACR TI-RADS demonstrated moderate diagnostic performance in the younger population. Lowering the thyroid nodule size criteria for FNAB leads to a higher detection rate of malignant, however, which at the cost of a significantly increased number of biopsies. Larger multicentric studies are required to customize the recommendation further before it can be accepted and used generally in the pediatric population.