Ultrasound-guided thyroid FNA: when to indicate it by ACR TI-RADS and ATA, technique, Bethesda and the report

Ultrasound-guided thyroid FNA is indicated by the sonographic pattern combined with nodule size: in ACR TI-RADS, from 1 cm in TR5, 1.5 cm in TR4 and 2.5 cm in TR3. The ATA and ETA use similar but not identical cutoffs, and the report must state which system was applied. Nodule classification is covered in our text on thyroid ultrasound and TI-RADS; here the focus is the puncture.

When to indicate it by ACR TI-RADS

The ACR advises describing up to four nodules, chosen by score and not by size, and sampling at most the two with the highest scores.

When to indicate it by ATA and ETA

The 2023 ETA guideline, with EU-TIRADS, uses over 10 mm in category 5, 15 mm in category 4 and 20 mm in category 3. It indicates puncture at any size when there is a pathological node or suspected extrathyroidal extension, and hyperfunctioning nodules are generally not punctured. Suspicious nodes are also sampled, with thyroglobulin washout if differentiated carcinoma is suspected.

A note on updates: the 2025 ATA guideline covers only differentiated cancer, and in 2026 the ATA opened a nodule-specific draft for comment. We did not find the final published version; check this before citing ATA 2015 as current.

Thyroid FNA technique

• Puncture under real-time ultrasound vision, by capillary action or suction (ETA).
• Fine needle, typically 25 or 27 G.
• In a mixed nodule, target the solid component.
• There is no single number of passes. A 2023 randomized trial showed no effect of the number of passes on adequacy in solid nodules.
• Severe coagulopathy is a contraindication. For the ETA, anticoagulation with an INR below 3 is not, and antiplatelet therapy is not an absolute contraindication.
• Hematoma is the most common complication, usually without symptoms; retropharyngeal hematoma is rare but can be serious.

Bethesda 2023: what comes back from cytology

The 2023 edition itself notes that cytology alone does not define management. The ETA considers repeating the puncture after a nondiagnostic result, Bethesda III, discordance between high-risk ultrasound and benign cytology, or significant growth.

What the report should include

• Target nodule: lobe, third, measurements and category, with the system used.
• Real-time ultrasound guidance and needle gauge.
• Number of passes per target and appearance of the material.
• Volume aspirated from a cystic component.
• Number of slides, fixative and material sent.
• Complications, or their absence.

Common mistakes

• Choosing the nodule by size rather than by score.
• Indicating FNA without citing the classification system.
• Puncturing the cystic center and missing the solid component.
• Forgetting the cervical nodes before the puncture.
• Not identifying which nodule was punctured, which prevents correlation with cytology.

See also our text on cervical ultrasound and lymph nodes.

How Laudário helps

In Laudário, the puncture has its own template:

• FNA template with targets added one by one: structure, location, measurement, classification, passes, appearance and volume of material.
• Needle gauge, complications and a Request tab for the cytopathology order.
• In the thyroid template, ACR TI-RADS is calculated by points and shows whether FNA is indicated by the longest axis.

Try it for 15 days free, no credit card required.

References

Tessler FN et al. ACR TI-RADS. J Am Coll Radiol 2017. Haugen BR et al. Thyroid 2016 (ATA 2015). Durante C et al. Eur Thyroid J 2023 (ETA). Ali SZ et al. The 2023 Bethesda System. Thyroid 2023.