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Thyroid ultrasound and TIRADS score: understanding your report

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Thyroid ultrasound and TIRADS score

Meaning of TIRADS 1, 2, 3, 4, 5 · When to perform fine-needle aspiration? When to monitor? When to treat? · Cochin AP-HP · Pr Anthony Dohan · Updated April 2026
TIRADS: Thyroid Imaging Reporting and Data System
The TIRADS score is a standardised system for classifying thyroid nodules on ultrasound, published by the ACR (American College of Radiology) in 2017. It harmonises ultrasound reports and guides clinical decisions (surveillance, fine-needle aspiration, treatment).
TIRADS scoreMeaningRisk of malignancyRecommended management
TIRADS 1Normal thyroid, no nodule0%No specific follow-up
TIRADS 2Benign nodule0%No fine-needle aspiration
TIRADS 3Probably benign nodule< 5%Surveillance if < 15 mm; FNA if > 15 mm
TIRADS 4Suspicious nodule5-20%FNA if > 10 mm
TIRADS 5Highly suspicious for malignancy> 20%FNA if > 5 mm

Quick answer

The ACR TIRADS score adds up points across 5 ultrasound criteria (composition, echogenicity, shape, margins, echogenic foci) to assess the risk of malignancy of a thyroid nodule and guide management.

The ultrasound criteria assessed

The ACR TIRADS score adds up points across 5 categories:

  1. Composition (cystic, spongiform, mixed, solid)
  2. Echogenicity (anechoic, hyperechoic, isoechoic, hypoechoic, markedly hypoechoic)
  3. Shape (wider than tall vs taller than wide)
  4. Margins (smooth, lobulated/irregular, extrathyroidal extension)
  5. Echogenic foci (microcalcifications, macrocalcifications, peripheral rim calcification, none)

The total number of points determines the TIRADS grade and the recommended management according to the size of the nodule.

Fine-needle aspiration (FNA): when and how?

Ultrasound-guided fine-needle aspiration (FNA) consists of sampling cells from the nodule under ultrasound guidance with a fine needle, for cytological analysis. It is painless (superficial local anaesthesia), performed as an outpatient consultation, and makes it possible to determine whether the nodule is benign or malignant in 85-90% of cases.

Frequently asked questions

My nodule is TIRADS 3: should I be worried?
No. TIRADS 3 means a probably benign nodule with a risk of malignancy below 5%. Ultrasound follow-up at 1 year is generally recommended. Fine-needle aspiration is only indicated if the nodule exceeds 15 mm or grows rapidly.
My nodule is TIRADS 4: what should I do?
TIRADS 4 means a suspicious nodule (5-20% risk of malignancy). Fine-needle aspiration is recommended if the nodule exceeds 10 mm. This does not mean you have cancer, but that verification is needed.
Can thyroid radiofrequency treat a TIRADS 4 nodule?
Radiofrequency is indicated for symptomatic nodules with confirmed benign status (Bethesda I-III cytology). It is not recommended before benignity has been confirmed by fine-needle aspiration.
What is the difference between TIRADS and Bethesda?
TIRADS is the ultrasound (imaging) classification. Bethesda is the cytological classification (results of the fine-needle aspiration, from Bethesda I = non-diagnostic to Bethesda VI = malignant). The two complement each other to guide the therapeutic decision.
Learn more
Radiofrequency ablation of thyroid nodules

Minimally invasive treatment of benign thyroid nodules by radiofrequency at Cochin AP-HP.

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On the same topic

Scientific references

Indications et contre-indications de la thermoablation des nodules thyroïdiens bénins (Indications and contraindications of thermal ablation of benign thyroid nodules)

Muller A, Villard N, Papadopoulos P, on behalf of the thyroid and ultrasound working group of the CERF, the SFR and the CIREOL (including Dohan A). J Imagerie Diagn Interv 2026. French national consensus.

2020 European Thyroid Association clinical practice guideline for the use of image-guided ablation in benign thyroid nodules

Papini E, Monpeyssen H, Frasoldati A, Hegedüs L. Eur Thyroid J 2020;9:172-185.

2017 Thyroid Radiofrequency Ablation Guideline: Korean Society of Thyroid Radiology

Kim JH, Baek JH, Lim HK, et al. Korean J Radiol 2018;19(4):632-655.

Why this page is trustworthy

Written by the Interventional Radiology team at Cochin Hospital AP-HP, Université Paris Cité. Medically reviewed by an interventional radiologist of the department. Last updated: July 2026.

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