Comparative Diagnostic Performance of Global Thyroid Ultrasound Risk Stratification Systems: The Impact of Nodule Size and Lexicon Standardization

Highlights

• Significant heterogeneity exists among the five major thyroid risk stratification systems (RSSs) regarding nodule classification and malignancy risk estimation.
• The American Thyroid Association (ATA) and EU-TIRADS prioritize sensitivity, leading to higher rates of unnecessary biopsies across all nodule sizes.
• The ACR TI-RADS maintains the lowest unnecessary biopsy rate (UBR) but at the cost of reduced sensitivity compared to other international systems.
• Nodule size (>2 cm vs. ≤2 cm) is a critical determinant of diagnostic performance, with K-TIRADS showing marked sensitivity shifts between size cohorts.

Background