Thyroid Imaging Reporting and Data System (TI-RADS).
FNA criteria as outlined in the table below
- A ≥20% increase in at least two nodule dimensions, with an increase of >2 mm.
- A ≥50% or greater increase in volume of a nodule.
If there is no change in size for 5 years, the nodule can be considered as having a benign behavior, and further follow up is not needed. Comparison should be made with the oldest study available, and not only the last one.
If there is interval growth, without fulfillment of FNA criteria, the next follow-up should be after 1 year, regardless of the TI-RADS category.
When there are multiple nodules, there should be no more than 4 nodules classified. FNA is not recommended of more than 2 nodules.
In the case of multiple nodules, the nodule with the highest TI-RADS FNA criteria should be sampled, which is not necessarily the dominant or largest nodule.