High suspicion | ≥ 1.0 cm | > 70%–90% |
Solid hypoechoic nodule or solid hypoechoic component of partially cystic nodule with ≥ 1 of the following features:
Irregular margins (infiltrative, microlobulated) Microcalcification Taller-than-wide shape Rim calcification with small extrusive soft tissue component Evidence of extrathyroidal extension
| | |
Intermediate suspicion | ≥ 1.0 cm | 10%–20% |
Hypoechoic solid nodule with smooth margin without the following:
Microcalcifications Extrathyroidal extension Taller-than-wide shape
| | |
Low suspicion | ≥ 1.5 cm | 5%–10% |
Isoechoic or hyperechoic solid nodule, or partially cystic nodule with eccentric solid area without any ultrasonographic features | | |
Very low suspicion | ≥ 2.0 cm | < 3% |
Spongiform or partially cystic without any ultrasonographic features | | |
Purely cystic nodules | No biopsy required | < 1% |