The TIRADS classification (Thyroid Imaging Reporting and Data System) is a standardized ultrasound evaluation system for thyroid nodules, based on morphological features and estimating the likelihood of malignancy.

There are various TIRADS systems: The one commonly used in Germany is the EU-TIRADS classification of the European Federation of Societies for Ultrasound in Medicine and Biology (European umbrella organization of national societies for ultrasound in medicine and biology).

 

 EU-TIRADS Classification [EFSUMB 2017]

Category

Ultrasound Criteria

Malignancy Risk

Recommendation

EU-TIRADS 1

Normal thyroid

0%

No further action required

EU-TIRADS 2

Benign features, e.g., pure cyst, spongiform nodule

0%

No FNA, no follow-up needed

EU-TIRADS 3

Low suspicion: iso-/hyperechoic, oval, smooth margins

<2%

FNA if >20 mm or follow-up

EU-TIRADS 4

Moderate suspicion: mildly hypoechoic, irregular margins, microcalcifications

6–17%

FNA recommended if >15 mm

EU-TIRADS 5

High suspicion: markedly hypoechoic, irregular, taller-than-wide, microcalcifications

>26%

FNA recommended if >10 mm, possible surgical evaluation