Computed tomography of the thyroid vascular, encapsulated structure made up of right and left lobes, which are connected at the midline by the isthmus. Each lobe is about 2 cm thick, 3 cm wide, and 5 cm long. The thyroid apex is located superiorly at the level of the mid-thyroid cartilage. The inferior margin of the gland is at the level of the fifth or sixth tracheal ring. The thyroid gland is encapsulated by the middle layer of deep cervical fascia and is part of the visceral space in the infrahyoid neck. It wraps around the trachea and is separated from the oesophagus by the
Computed tomography of the thyroid aerodigestive axis or vascular structures are not technically possible in the absence of IV contrast administration. For these reasons, 18FDG-PET/CT utilizing contrast administration should be considered for most patients with extensive disease. Metastasis to the thyroid is rare and represents 5.5 % of biopsied thyroid malignancies. It is commonly found with cancers originating from the breast, renal cell, lung, melanoma, and colon. Direct invasion from adjacent structures such as the pharynx, larynx, trachea, or oesophagus has been reported (Fig. 10). Metastatic disease has a non-specific appearance. Presence of ITNs in patients with another known malignancy is a common clinical problem