Current Imaging Techniques for Thyroid Nodules and Thyroid Cancer

Thyroid nodules are increasingly detected in clinical practice, and accurate imaging evaluation is essential for risk stratification, treatment planning, and postoperative surveillance of thyroid cancer. Although ultrasound remains the first-line modality for thyroid nodule assessment, the roles of computed tomography (CT), spectral CT, magnetic resonance imaging (MRI), and positron emission tomography-computed tomography (PET-CT) vary across clinical scenarios, and the optimal integration of these modalities remains insufficiently standardized. In particular, existing studies often focus on individual imaging techniques, while practical guidance on modality selection for initial screening, preoperative anatomical assessment, recurrence monitoring, and high-risk disease evaluation remains limited. This narrative review summarizes the imaging principles, clinical indications, diagnostic value, advantages, and limitations of ultrasound, CT, spectral CT, MRI, and PET-CT in the evaluation of thyroid nodules and thyroid cancer. Future advances should focus on standardized multimodal imaging strategies, quantitative functional imaging, radiomics, and carefully validated artificial intelligence-assisted approaches to improve individualized diagnosis and management of thyroid nodules and thyroid cancer.