European Thyroid Association Guidelines for Ultrasound Malignancy Risk Stratification of Thyroid Nodules in Adults: The EU-TIRADS

Abstract

Thyroid ultrasound (US) is a key examination for the management of thyroid nodules. Thyroid US is easily accessible, noninvasive, and cost-effective, and is a mandatory step in the workup of thyroid nodules. The main disadvantage of the method is that it is operator dependent. Thyroid US assessment of the risk of malignancy is crucial in patients with nodules, in order to select those who should have a fine needle aspiration (FNA) biopsy performed. Due to the pivotal role of thyroid US in the management of patients with nodules, the European Thyroid Association convened a panel of international experts to set up European guidelines on US risk stratification of thyroid nodules. Based on a review of the literature and on the American Association of Clinical Endocrinologists, American Thyroid Association, and Korean guidelines, the panel created the novel European Thyroid Imaging and Reporting Data System, called EU-TIRADS. This comprises a thyroid US lexicon; a standardized report; definitions of benign and low-, intermediate-, and high-risk nodules, with the estimated risks of malignancy in each category; and indications for FNA. Illustrated by numerous US images, the EU-TIRADS aims to serve physicians in their clinical practice, to enhance the interobserver reproducibility of descriptions, and to simplify communication of the results.

Keywords: Fine needle aspiration; Guidelines; Risk of malignancy; TIRADS; Thyroid nodule; Ultrasound.

Fig. 1.

Example of a drawing to locate and number thyroid nodules.

Fig. 2.

EU-TIRADS 2: pure/anechoic cyst. Transverse (left) and longitudinal (right) planes.

Fig. 3.

EU-TIRADS 2: spongiform nodule. Transverse plane.

Fig. 4.

EU-TIRADS 3: low-risk isoechoic nodule with an oval shape and smooth margins without any high-risk features. Longitudinal (left) and transverse (right) planes.

Fig. 5.

EU-TIRADS 3: low-risk hyperechoic nodule with an oval shape and smooth margins without any high-risk features. Longitudinal (left) and transverse (right) planes.

Fig. 6.

EU-TIRADS 3: grouped low-risk isoechoic nodules with an oval shape and smooth margins without any high-risk features. Longitudinal plane.

Fig. 7.

EU-TIRADS 4: intermediate-risk, mildly hypoechoic nodule with an oval shape and smooth margins without any high-risk features. Longitudinal (left) and transverse (right) planes.

Fig. 8.

EU-TIRADS 5: high-risk nodule with a taller-than-wide shape, irregular margins, microcalcifications, and marked hypoechogenicity. Longitudinal (left) and transverse (right) planes. 11 × 8 × 11 mm (length × width × thickness).

Fig. 9.

EU-TIRADS 5: high-risk nodule with a non-oval shape, spiculated margins, microcalcifications, and marked hypoechogenicity. Longitudinal (left) and transverse (right) planes.

Fig. 10.

EU-TIRADS 5: two different examples of high-risk hypoechoic nodules with lobulated margins in the transverse (left picture) and longitudinal (right picture) planes.

Fig. 11.

EU-TIRADS 5: high-risk nodule with a taller-than-wide shape in the transverse plane.

Fig. 12.

Algorithm of EU-TIRADS for malignancy risk stratification and fine-needle aspiration (FNA) decision-making. * FNA should be performed in case suspicious lymph nodes are found.