CQ6. What Are the Imaging Studies Most Suitable for the Diagnosis of Thyroid Carcinoma and What Are Their Sensitivity, Specificity, and Likelihood Ratio?

Imaging studies typically used in the diagnosis of malignant thyroid tumor include ultrasonography, CT, MRI, and scintigraphy. Some studies are performed with the explicit purpose of differentiating malignant from benign tumors, while others are performed with other objectives and incidentally result in the discovery of thyroid tumors. Most of the former are done by ultrasonography, which is not only increasingly better defined in B mode images of late, but has other features such as color Doppler, power Doppler, Doppler analysis, and elastography. Most of the latter are seen in CT scans and FDG-PET scans. These and also ¹²³Tl scintigraphy and ²⁰¹Tl scintigraphy are evaluated for their utility in differential diagnosis in the following section.