Validation of the modified 4-tiered categorization system through comparison with the 5-tiered categorization system of the 2015 American Thyroid Association guidelines for classifying small thyroid nodules on ultrasound.

Validation of the modified 4-tiered categorization system through comparison with the 5-tiered categorization system of the 2015 American Thyroid Association guidelines for classifying small thyroid nodules on ultrasound.