Visualizing thyroid health: a pictorial journey through 2017 ACR TI-RADS and common thyroid pathologies

With the advent of high-resolution ultrasonography (HRUS), more thyroid nodules are being detected than ever before, and they are being identified at an earlier stage. It poses a challenge for radiologists and clinicians in deciding what to do next. Most nodules are benign and require no follow-up and intervention. Even highly suspicious nodules can be followed up, if the size is small. Variations in HRUS interpretation among radiologists are common, with frequent misidentifications between spongiform and solid-cystic lesions, hypoechoic and very hypoechoic nodules, and microcalcification and hyperechoic foci with comet-tail artifacts. Cystic lesions with echogenic contents are often confused with solid nodules, cystic papillary carcinoma thyroid is often confused with colloid cysts. The 2017 ACR TI-RADS (American College of Radiology Thyroid Imaging Reporting and Data System) aims to standardize the interpretation of thyroid nodules and guide further management. Rather than giving specific diagnosis like colloid cyst, adenomatous nodule and papillary carcinoma; ACR TI-RADS classifies nodules from TI-RADS 1 to TI-RADS 5 based on HRUS characteristics and recommends further management. What the authors often read are textual contents that are theoretical, and in practice, the authors get confused while interpreting the characteristics of thyroid nodules. This review offers a detailed visual overview of the 2017 ACR TI-RADS and common thyroid conditions, explaining key features through imaging data and examples for consistent interpretation. Combining textual explanations with visual aids, this article provides practical guidance for interpreting thyroid nodules for radiologists, and clinicians seeking a clear understanding of thyroid imaging and pathology.