Artículo original: Hyobin Seo, Dong Gyu Na, Ji-Hoon Kim, Kyung Won Kim, Ji Won Yoon. Ultrasound-Based Risk Stratification for Malignancy in Thyroid Nodules: A Four-Tier Categorization System. Eur Radiol (2015) 25:2153-62 Sociedad a la que pertenece: European Society of Radiology…