Diagnostic performance of the 2021 Korean thyroid imaging reporting and data system in pediatric thyroid nodules

Objectives To evaluate the diagnostic performance of 2021 K-TIRADS biopsy criteria for detecting malignant thyroid nodules in a pediatric population, making comparisons with 2016 K-TIRADS. Methods This retrospective study included pediatric patients with histopathologically confirmed diagnoses. The diagnostic performance of 2021 K-TIRADS was compared with that of 2016 K-TIRADS. Simulation studies were performed by changing biopsy cut-off sizes for K-TIRADS 5 to 1.0 cm (K-TIRADS(5-1.0cm)) and 0.5 cm (K-TIRADS(5-0.5cm)), and for K-TIRADS 4 to 1.0 cm (K-TIRADS(4-1.0cm)) and 1.0-1.5 cm (K-TIRADS(4-1.0 similar to 1.5cm)). Subgroup analysis was performed in small (< 1.5 cm) and large nodules (>= 1.5 cm). Results Two hundred seventy-seven thyroid nodules (54.9% malignant) from 221 pediatric patients were analyzed. All simulated 2021 K-TIRADS showed higher accuracy than 2016 K-TIRADS. Compared with 2021 K-TIRADS(5-1.0cm), 2021 K-TIRADS(5-0.5cm) showed lower specificity (51.6% vs. 47.9%; p = 0.004) but higher sensitivity (77.2% vs. 90.3%; p < 0.001) and accuracy (62.7% vs. 68.9%; p < 0.001). Compared with 2021 K-TIRADS(4-1.0cm), 2021 K-TIRADS(4-1.0 similar to 1.5cm) showed higher specificity (44.9% vs. 47.9%; p = 0.018) without significant difference in other diagnostic measures. Compared with 2016 K-TIRADS, 2021 K-TIRADS (biopsy cut-offs, 0.5 cm for K-TIRADS 5; 1.0-1.5 cm for K-TIRADS 4) showed higher sensitivity (34.0% vs. 67.3%; p < 0.001) while maintaining specificity (89.4% vs. 88.2%; p = 0.790) in small nodules, and higher specificity (5.9% vs. 25.4%; p < 0.001) while maintaining sensitivity (100% vs. 98.7%; p = 0.132) in large nodules. Conclusions In pediatric patients, 2021 K-TIRADS showed superior diagnostic accuracy to 2016 K-TIRADS, especially with a biopsy cut-off of 0.5 cm for K-TIRADS 5 and 1.0-1.5 cm for K-TIRADS 4.

Automated summary

This study evaluated the diagnostic performance of the 2021 K-TIRADS biopsy criteria for detecting malignant thyroid nodules in a pediatric population and compared it with the 2016 K-TIRADS. The results showed that the 2021 K-TIRADS had superior diagnostic accuracy to the 2016 K-TIRADS, especially with a biopsy cut-off of 0.5 cm for K-TIRADS 5 and 1.0-1.5 cm for K-TIRADS 4.