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 the possible undesired interference of free iodide contrast medium with thyroid iodide I-131 uptake for 6–8 weeks or more. This would adversely affect the management of these patients by delaying diagnostic thyroid scintigraphy and radioiodine ablation in patients with DTCs for 2–6 months. The radiologist must evaluate the central structures draping the thyroid gland including the trachea, oesophagus, larynx, and pharynx, as well as the recurrent laryngeal nerve. Invasion is suspected if the thyroid mass abuts the airway or oesophagus for more than 180 degrees. Luminal deformity, mucosal thickening, and mucosal focal irregularity are more specific indicators of invasion. Obliteration