Computed tomography of the thyroid ,88 and and9).9). CT scans are also the most sensitive diagnostic tool for the detection of pulmonary micro-metastases. Many of the neck US features that are considered as suggestive signs of disease recurrence are also applicable to CT examination. These signs might include sizable rounded nodules in the thyroid bed, fine calcifications, or cystic change. In cases of elevated thyroglobulin with negative neck US and iodine whole body scintigraphy (WBS), fluorodeoxyglucose (FDG) positron emission tomography (PET) is the next modality of choice. Dedifferentiated thyroid carcinoma usually has avid FDG-PET uptake and a negative radioiodine scan, typically does not respond to
Computed tomography of the thyroid should be directed to the upper extent of the goiter and structures immediately surrounding the thyroid gland, including the neuro-vascular structures, retropharyngeal space, and pre-vertebral space. The reporting radiologist should evaluate the vocal cords for symmetry and signs of vocal cord palsy. Inflammatory thyroid disorders include acute infectious thyroiditis, Hashimoto’s thyroiditis, Riedel’s thyroiditis, and granulomatous thyroiditis (de Quervain’s). Hashimoto’s thyroiditis is associated with an increased risk of lymphoma and papillary thyroid carcinoma. The CT scan findings of thyroiditis are nonspecific and variable (Figs. 14, ,1515 and and16)16). The thyroid gland has a very high iodine concentration, resulting in high CT