EU-TIRADS is a reporting system designed by the European Thyroid Association for ultrasound assessment of thyroid nodules and stratification of requirement for FNA and malignancy. This system was based on an established French system, with validated results ^2,3.

This is a five stage system using descriptive, pattern recognition findings on ultrasound, and size measurement.

Ultrasound features

Assessment of the following features as well as size, location and number of nodules are recommended in the reporting of EU-TIRADS:

• echogenicity

  • anechoic / spongiform (benign)

  • isoechoic / hyperechoic (low risk)

  • mildly hypoechoic (intermediate risk)

  • markedly hypoechoic (high risk)

• shape

  • oval

  • non-oval (high risk)

• margin

  • smooth

  • irregular (high risk)

• microcalcifications (high risk)

Classification

• EU-TIRADS 1: no nodule

• EU-TIRADS 2: benign

• EU-TIRADS 3: low risk (oval, smooth margin, iso / hyperechoic, no high risk features)

• EU-TIRADS 4: intermediate risk (oval, smooth margin, mildly hypoechoic, no high risk features)

• EU-TIRADS 5: any high risk features (non-oval, irregular margin, microcalcifications, marked hypoechogenicity)

Recommendations

• EU-TIRADS 2: no FNA required (unless for theraputic purpose / relieve compression)

• EU-TIRADS 3: >20 mm FNA

• EU-TIRADS 4: >15 mm FNA

• EU-TIRADS 5: >10 mm FNA, <10 mm consider FNA or active surveillance

Regardless of US appearance, if the nodule is hot on scintigraphy then the lesion is almost certainly benign and does not require sampling.

Risk of malignancy

• EU-TIRADS 1: n/a

• EU-TIRADS 2: 0%

• EU-TIRADS 3: low risk (2-4%)

• EU-TIRADS 4: intermediate risk (6-17%)

• EU-TIRADS 5: high risk (26-87%)

Comparison with other classification systems

The EU-TIRADS system was published in 2017, following K-TIRADS (2016) and ACR TI-RADS (2017). Other systems including the ATA and SRU are also in regular use.

A number of comparative studies of the systems ^4,5 show the EU-TIRADS system has sensitivity 83-86% and specificity 32-79%. The rate of unnecessary FNA was 25%, again the intermediate of the three TIRADS.

Good interobserver agreement regarding decision to biopsy has also been shown (Cohen kappa 0.68) ⁶.

External links

• EU-TIRADS calculator for thyroid ultrasound - Radcalculator.org

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