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 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