Abstract

The thyroid imaging has evolved from early radionuclide thyroid scanning to the development of the advanced technique of SPECT, PET and fusion imaging. The advancement in cross-sectional techniques such as USG, CT and MRI has further improved the evaluation of intrathyroid pathologies. OCT has supplemented the imaging for better selection of patients for operation. Ultrasound can be used as the primary imaging modality for guiding treatment of patients with CH, potentially decreasing radiation exposure and cost. Scintigraphy can be reserved for the few patients with equivocal ultrasound findings, such as hypoplastic thyroid gland. The thyroid is a 2-inch-long, butterfly-shaped gland weighing less than 1 ounce. Located in the front of the neck below the larynx, or voice box, it has two lobes, one on each side of the windpipe. The thyroid gland makes two thyroid hormones, triiodothyronine (T3) and thyroxine (T4). T3 is made from T4 and is the more active hormone, directly affecting the tissues. Thyroid hormones affect metabolism, brain development, breathing, heart and nervous system functions, body temperature, muscle strength, skin dryness, menstrual cycles, weight, and cholesterol levels. Hypothyroidism is the common clinical condition of thyroid hormone deficiency and, if left untreated, can lead to serious adverse health effects on multiple organ systems, with the cardiovascular system as the most robustly studied target. Overt primary hypothyroidism is defined as elevated thyroid-stimulating hormone (TSH) concentration in combination with free thyroxine (fT4) concentration below the reference range

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