Thyroid nodules are among the most frequent findings in diagnostic imaging, often discovered incidentally during scans of the neck or chest. While most nodules are benign, determining which require further investigation is a common challenge for radiologists. Over-investigation can lead to unnecessary biopsies, surgery and anxiety, whereas missed malignancies may delay care. The European Society of Head and Neck Radiology (ESHNR) elaborated a new set of recommendations to guide radiologists in evaluating thyroid nodules, diffuse thyroid disease and thyroid cancer. These guidelines emphasise evidence-based use of ultrasound, risk stratification systems such as ACR TI-RADS and EU-TIRADS, and interdisciplinary collaboration to ensure accurate, efficient and patient-centred management.
Managing Incidental Thyroid Nodules
Incidental thyroid nodules (ITNs) are frequently identified on cross-sectional imaging, with prevalence rates reaching up to one-quarter of adults. The majority are benign, while malignant ITNs usually represent well-differentiated thyroid cancers (DTCs) with favourable outcomes. US remains the preferred modality for further characterisation, offering superior resolution and diagnostic accuracy compared with CT or MRI. The introduction of risk stratification scoring (RSS) systems, such as ACR TI-RADS and EU-TIRADS, allows radiologists to classify nodules consistently and determine when fine-needle aspiration (FNA) is warranted.
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Evidence shows that routine investigation of ITNs without suspicious sonographic features offers little clinical benefit and may expose patients to unnecessary risk. The concept of overdiagnosis—detecting indolent disease that would not affect survival—has been highlighted by national screening experiences showing large increases in thyroid cancer diagnoses without changes in mortality. In older populations, where most deaths are unrelated to thyroid disease, further imaging often brings limited value. Physical risks of overtreatment include surgical complications and lifelong hormone replacement, while psychological effects such as anxiety and depression are common even in patients with benign or indolent disease. From an economic standpoint, extensive ITN workup imposes high costs, with projected national expenditures in the billions for low-risk disease management. Consequently, selective investigation of nodules based on validated criteria is strongly recommended to prevent harm and preserve resources.
Role of Ultrasound and Risk Stratification Systems
US is the gold standard for thyroid imaging, underpinning the use of structured RSS frameworks that guide biopsy decisions. ACR TI-RADS and EU-TIRADS are the two most widely used systems. ACR TI-RADS applies a point-based algorithm assigning malignancy risk from TR1 (benign) to TR5 (high suspicion), with specific FNA thresholds based on both size and category. EU-TIRADS, endorsed by the European Thyroid Association, uses a pattern-based approach, classifying nodules from EU-TIRADS 1 to 5 and recommending FNA for lesions exceeding defined size limits within each category. Although their methods differ, both systems have shown comparable diagnostic performance. ACR TI-RADS tends to reduce unnecessary FNAs due to stricter criteria, while EU-TIRADS prioritises sensitivity for malignancy detection. The adoption of either ensures consistent reporting and evidence-based management, with an international harmonisation effort (I-TIRADS) underway to unify terminology and standards.
For diffuse thyroid disorders such as Hashimoto’s thyroiditis and Graves’ disease, US also provides characteristic imaging signatures. Hashimoto’s disease typically presents with patchy hypoechogenicity and micronodular texture, while Graves’ disease displays homogeneous hypoechogenicity and marked vascularity. Structured reporting systems, such as DTD-TIRADS, enhance diagnostic reproducibility and facilitate follow-up. Functional imaging with scintigraphy is reserved for hyperthyroid cases requiring differentiation between Graves’ disease and toxic multinodular goitre. In most patients, management decisions are guided by thyroid function tests alongside imaging findings.
Imaging and Management of Thyroid Cancer
Thyroid cancer (TC) accounts for a small proportion of global malignancies but represents the most common endocrine cancer. Its rising incidence reflects advances in imaging rather than a true increase in disease occurrence, as mortality remains stable. Differentiated thyroid carcinomas, including papillary and follicular subtypes, comprise the majority of cases and typically have excellent prognoses. Molecular and histological profiling has become increasingly relevant, with BRAF mutations in papillary carcinoma linked to poorer outcomes. The World Health Organization now endorses mutation-specific immunohistochemistry in diagnostic practice.
US is the first-line tool for tumour detection, guiding FNA and lymph node evaluation. CT and MRI provide staging information in advanced disease, while PET-CT serves specific roles such as detecting residual or recurrent cancer when radioiodine scans are negative. Core biopsy is reserved for suspected lymphoma or anaplastic thyroid carcinoma (ATC), both of which require urgent management. For medullary thyroid carcinoma (MTC), PET with 68Ga-DOTATATE enhances staging accuracy due to somatostatin receptor affinity. Despite these technological advances, the cornerstone of optimal TC management remains multidisciplinary collaboration among radiologists, endocrinologists, surgeons, pathologists and nuclear medicine specialists. Coordinated decision-making ensures appropriate use of imaging, limits overtreatment and supports tailored patient care.
Thyroid imaging plays a central role in balancing diagnostic accuracy with patient safety and resource efficiency. The ESHNR recommends reserving further investigations for nodules with high-risk features, using standardised RSS systems such as ACR TI-RADS or EU-TIRADS and fostering interdisciplinary cooperation in thyroid cancer management. Evidence indicates that most incidental nodules are benign and that routine evaluation of asymptomatic lesions contributes little to patient outcomes while increasing anxiety, costs and overtreatment. By applying structured ultrasound-based criteria and adhering to clinical context, radiologists can ensure high-value, patient-centred thyroid care.
Source: European Radiology
Image Credit: iStock
