Assessment of the American College of Radiology Thyroid Imaging Reporting and Data System for Thyroid Nodule Malignancy Risk Stratification in a Pediatric Population

OBJECTIVE. The purpose of this study is to assess the diagnostic performance of the American College of Radiology (ACR) Thyroid Imaging Reporting and Data System (TIRADS) for malignancy risk in pediatric thyroid nodules. MATERIALS AND METHODS. Two radiologists reviewed ultrasound images of 74 tissue-proven thyroid nodules in 62 children. Points were given for individual features and then added to determine the ACR TI-RADS category, ranging from 1 (benign) to 5 (high suspicion). Kappa coefficients were generated to assess intra- and interobserver agreement. Generalized linear mixed-effects models were used to estimate the odds of malignancy with construction of a supplementary ROC curve. RESULTS. Fifty-four nodules were benign and 20 were malignant, with a median ACR TI-RADS category of 4 (interquartile range, 4-5). Nineteen of 20 (95.0%) malignant nodules were rated as TI-RADS category 4 or 5. There was substantial intraobserver agreement (k = 0.69-0.77; p < 0.001) and moderate interobserver agreement (k = 0.37; p = 0.002) for TI-RADS category. Univariable analysis showed that, with every 1-unit increase of TI-RADS category, the likelihood of malignancy increased 2.63 times (95% CI, 1.08-6.41; p = 0.03). After adjusting for nodule size, TI-RADS category remained marginally associated with malignancy (adjusted odds ratio, 2.27; 95% CI, 0.93-5.54; p = 0.07). The AUC was 0.75 (95% CI, 0.64-0.86). An optimal cut point of TI-RADS category 5 was selected, with TI-RADS category 5 nodules 10.44 times (95% CI, 2.71-40.21; p < 0.0001) more likely than categories 1-4 nodules to be malignant. CONCLUSION. ACR TI-RADS discriminates well between malignant and benign nodules in a pediatric population, particularly at TI-RADS category 5.