Computed tomography of the thyroid bone, before it loops posteriorly and inferiorly to the hyoid bone. Then it continues its descent into the infra-hyoid portion of the neck, anterior to the trachea, thyroid cartilage, and thyroid membrane. Any thyroid residual along the descent course may lead to the development of ectopic thyroid glands. Thyroid carcinomas, thyroiditis, and goiter may develop within any ectopic thyroid tissue. Thyroid scanning with technetium-99 m (Tc99m) plays an important role in detecting orthotopic and ectopic thyroid tissue. Both CT scans and US can help detect ectopic tissue when a lesion demonstrates imaging and enhancement characteristics of thyroid tissue. The absence
Computed tomography of the thyroid have variable CT scan findings, such as calcifications, single or multiple nodules, cysts, or diffuse enlargement. Thyroid calcifications on a CT scan can be seen in both benign and malignant thyroid lesions. Sonographic examination of the thyroid can differentiate between micro-calcifications, which are highly associated with papillary thyroid carcinoma, and eggshell calcifications, which favour a benign process such as colloid cysts (Figs. 1 and and2)2). In a retrospective review of preoperative CT scan, 35 % (135 of 383) of the patients had detectable intra-thyroidal calcifications. Among them, 48 % had a histopathologically proven thyroid cancer. Calcified nodules had a significantly