An ultrasound of the thyroid produces pictures of the thyroid gland and the adjacent structures in the neck. It is one of nine endocrine glands located throughout the body that make and send hormones into the bloodstream.
The thyroid gland is located in front of the neck just above the collar bones and is shaped like a butterfly, with one lobe on either side of the neck connected by a narrow band of tissue.
The thyroid gland makes the thyroid hormone, which helps to regulate a variety of body functions including how fast the heart beats. It is very common for patchy areas or nodules to develop in the thyroid that may or may not be felt on the skin surface. About five to 10 percent of adults will have lumps in their thyroid that a doctor can identify on an exam. These are called palpable nodules. Ultrasound is very sensitive and shows many nodules that cannot be felt. In some age groups, nodules are seen on ultrasound in as many as 70 percent of adults. The vast majority of these are benign regions of thyroid tissue that pose no health risk. The minority of these are true tumors of the thyroid and may require further diagnosis or treatment.
An ultrasound of the thyroid is typically used:
- to determine if a lump in the neck is arising from the thyroid or an adjacent structure
- to analyze the appearance of thyroid nodules and determine if they are the more common benign nodule or if the nodule has features that require a biopsy
- to look for additional nodules in patients with one or more nodules felt on physical exam
- to see if a thyroid nodule has substantially grown over time