| Ultrasonographic Pattern | Ultrasonographic Characteristics | Estimated Risk of Malignancy | FNA Size Cutoff (largest dimension) |
| High suspicion | Solid hypoechoic nodule or solid hypoechoic component of a partially cystic nodule with one or more of the following features: irregular margins (infiltrative, microlobulated), microcalcifications, taller than wide shape, rim calcifications with small extrusive soft tissue component, evidence of extra thyroid extension (ETE) | Greater than 70% - 90% | FNA at equal or greater than 1 cm |
| Intermediate suspicion | Hypoechoic solid nodule with smooth margins without microcalcifications, ETE, or taller than wide shape | 10% al 20% | FNA at equal or greater than 1 cm |
| Low suspicion | Isoechoic or hyperechoic solid nodule, or partially cystic nodule with eccentric solid areas, without microcalcification, irregular margin or ETE, or taller than wide shape | 5% al 10% | FNA at equal or greater than 1.5 cm |
| Very low suspicion | Spongiform or partially cystic nodules without any of the sonographic features described in low, intermediate, or high suspicion patterns | Less than 3% | Consider FNA at equal or greater 2 cm Observation without FNA is also an option |
| Benign | Purely cystic nodules (no solid component) | Less than 1% | No biopsy |