TI-RADS ACRTags: Thyroid Imaging Reporting and Data System, endocrinology, oncologyComposition: Cystic or almost completely cystic; Spongiform, composed predominantly (> 50 %) of small cystic spaces. Do not add further points for other categories; Mixed cystic and solid, assign points only for predominant solid component; Solid, or almost completely solid, or composition cannot be determined because of calcification. Echogenicity: Anechoic (Cystic or almost completely cystic); Hyper- èëè isoechoic (copmared to adjacent parenchyma), or if echogenicity cannot be determined; Hypoechoic (copmared to adjacent parenchyma); Very hypoechoic (more than strap muscles). Shape: Wider-than-tall; Taller-than-wide (should be assessed on a transverse image with measurement parallel to ultrasound beam for height and perpendicular for width). Margin: Smooth; Ill defined, or if margin cannot be determined; Lobulated (protrusion into adjacent tissue) or irregular (jagged, spiculated or sharp angles) Extra-thyroidal extension. Echogenic Foci: None or large comet-tail artifacts (V-shaped, > 1 mm, in cystic component); Macrocalcifications (with acoustic shadowing); Peripheral (rim) calcifications (complete or incomplete along margin); Punctate echogenic foci (may have small comet-tail artifacts). *Also see calculator Thyroid volume*For abbreviations, see Dictionary