Spongiform: Composed predominantly (>50%) of small cystic spaces. Do not add further points for other categories.
Mixed cystic and solid: Assign points for predominant solid component.
Assign 2 points if composition cannot be determined because of calcification.
Anechoic: Applies to cystic or almost completely cystic nodules.
Hyperechoic/isoechoic/hypoechoic: Compared to adjacent parenchyma.
Very hypoechoic: More hypoechoic than strap muscles.
Assign 1 point if echogenicity cannot be determined.
Taller-than-wide: Should be assessed on a transverse image with measurements parallel to sound beam for height and perpendicular to sound beam for width.
This can usually be assessed by visual inspection.
Lobulated: Protrusions into adjacent tissue.
Irregular: Jagged, spiculated, or sharp angles.
Extrathyroidal extension: Obvious invasion = malignancy.
Assign 0 points if margin cannot be determined.
Large comet-tail artifacts: V-shaped, >1 mm, in cystic components.
Macrocalcifications: Cause acoustic shadowing.
Peripheral: Complete or incomplete along margin.
Punctate echogenic foci: May have small comet-tail artifacts.
2017 White Paper of the ACR TI-RADS Committee