Thyroid Sonography: Nuclear Medicine Point of View

Purpose of Review: The American Cancer Society estimated that cancer of the thyroid causes 53,990 new cases and about 2060 deaths in 2018. The chance of being diagnosed with thyroid cancer has risen and this increment seems to be the result of increased use of ultrasound, CT and MR imaging examinations for reasons unrelated to the thyroid. Up to 50% of adults in central Europe have one or multiple thyroid nodules. However, the prevalence of latent carcinoma in an unselected autopsy study was 8.6%. The main diagnostic task is to differentiate between benign and malignant lesions, preferably based upon on ultrasound parameters or scoring systems like TI-RADS. Recent Findings: Although there are no pathognomonic features for malignant thyroid nodules at ultrasonography or any other imaging modality, sonography of the thyroid gland has beyond doubt become the imaging method of choice for the last three decades, combined with FNA in suspicious cases. Summary: Several technological improvements like ultrasound elastography, and a proliferating literature of different scoring systems allow the conclusion that ultrasound is an important gatekeeper for further diagnostic steps but not capable, so far, to identify autonomy or malignancy with a sufficiently high accuracy.