Most people will develop a thyroid nodule during their lifetime. Thyroid nodules are a frequent finding on neck sonography. Radiologists or clinicians who interpret thyroid ultrasonography images frequently face the dilemma of how to report nodules and suggest the next step of the management.
　　This talk will review the new risk-stratification system for classifying thyroid nodules on the basis of their appearance at ultrasonography, published by the Thyroid Imaging Reporting and Data System (TI-RADS) Committee of the American College of Radiology (ACR) in 2017, which is designed for identify most clinically significant malignancies while reducing the number of biopsies performed on benign nodules.
　　The ACR TI-RADS recommendations provide guidance regarding management of thyroid nodules on the basis of their ultrasound appearance. Points in five feature categories are summed to determine a risk level from TR1 to TR5. Recommendations for fine needle aspiration(FNA) or image follow-up are based on the TI-RADS level and its maximal diameter.
　　The practical issues of reporting process using TI-RADS and our experiences would also be covered in this section.