U/S can be used to risk-stratify using the Thyroid Imaging Reporting and Data System (TI-RADS) (http://tiradscalculator.com/)
Solid nodule
- With suspicious sonographic features >1.0 cm
- Without suspicious sonographic features >1.5 cm
Mixed cystic-solid nodule
- With suspicious sonographic features: hypoechoic, Solid component >1.0 cm
microcalcifications, infiltrative margins, taller than
wide in transverse plane - Without suspicious sonographic features: Spongiform Solid component >1.5 cm
nodules, isoechoic of hyper echoic solid nodules, mixed
solid-cystic nodules without above suspicious features
Spongiform nodule (multiple microcystic components >2.0 cm
in >50% of volume of nodule
Suspicious cervical lymph node: May consider biopsy of lymph node
Above criteria are general guidelines: With high risk clinical features, evaluation of smaller nodules may be indicated based on clinical concerns e.g. prior thyroid cancer, radiation exposure, 1st degree relative with thyroid cancer of MEN2, FDG avid on PET scan, thyroid cancer associated history e.g. familial adenomatous polyposis, Carney complex, Cowden syndrome
African Head & Neck Society (AfHNS) Clinical Practice Guidelines for Head & Neck Cancers in Developing Countries and Limited Resource Settings 