title: Thyroid abnormality secondary to tortuous carotid artery.
abstract: A 59-year-old man was referred to the nuclear medicine service for a thyroid scan, as his neck was thick and the thyroid was not palpable. In the past the patient had undergone head and neck irradiation for acne. A 123I-thyroid scan was interpreted as a "cold" nodule in the lower pole of the right lobe, but thyroid ultrasound showed no thyroid abnormality. Repeat ultrasound examination eventually showed a tortuous carotid artery behind the lower pole of the right lobe of the thyroid that corresponded to the "cold" defect.
mesh_terms: D002339:Carotid Arteries / Q000002:abnormalities*; D005189:False Positive Reactions; D006801:Humans; D007457:Iodine Radioisotopes; D008297:Male; D008875:Middle Aged; D011877:Radionuclide Imaging; D013964:Thyroid Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging; D014463:Ultrasonography
chemical_list: D007457:Iodine Radioisotopes