Thyroid dysgenesis thyroid gland may be located anywhere along the path of the descent of the thyroid during its embryological development, although it is most commonly located at the base of the tongue, just posterior to the foramen cecum of the tongue. In this location, an aberrant or ectopic thyroid gland is known as a "lingual thyroid". If the thyroid fails to descend to even higher degree, then the resulting final resting point of the thyroid gland may be high in the neck, such as just below the hyoid bone. Parts of ectopic thyroid tissue ("accessory thyroid tissue") can also occur, and
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