RESUMO
Thyroid nodules are extremely common. Ultrasonography is the most effective imaging modality to diagnose and differentiate thyroid nodules. There are many versions of thyroid image reporting and data system(TI-RADS) evaluated by ultrasound, but some classification system indexes are complicated and clinical application is chaotic. In 2017, the American College of Radiology (ACR) published white papers that introduced a TI-RADS classification system based on conventional ultrasound to reduce the dependence on operators and facilitate communication with physicians. The purpose of the ACR TI-RADS is to establish the risk classification system for managing thyroid nodules and guide the physicians to make professional judgments. The ACR TI-RADS risk classification system is interpreted in this article, including the development, overview and feature categories of ACR TI-RADS, and authors' experiences in clinical application.