Ultrasound imaging of the thyroid produces images of the thyroid gland and the adjacent structures in the neck. The thyroid is one of nine endocrine glands located throughout the body that produce 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.

Ultrasound imaging uses a small probe, called a transducer, and gel placed directly on the skin. High-frequency sound waves travel from the probe, through the gel, into the body. The probe collects the sounds that bounce back. A computer uses those sound waves to create the images for the exam.

Ultrasound is painless and non-invasive.

Your medical provider may recommend a thyroid ultrasound to:

• determine if a lump in the neck is arising from the thyroid or an adjacent structure
• analyze the appearance of thyroid nodules and determine if they are the more common benign nodule or if the nodule is suspicious and will require a biopsy
• look for additional nodules in patients with one or more nodules felt on physical exam
• see if a thyroid nodule has substantially grown over time.

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 malignant tumors of the thyroid and may require further diagnosis or treatment.

For most ultrasound exams, you will lie on your back on an exam table. You may have your position adjusted to either side in order to improve the quality of the images captured during the exam.

An ultrasound technologist will apply a warm water-based gel to the area of the body being studied. The gel will help the transducer make secure contact with the body and eliminate air pockets between the transducer and the skin that can block the sound waves from passing into your body. The transducer is placed on the body and moved back and forth over the area of interest until the desired images are captured.

There is usually no discomfort from pressure as the transducer is pressed against the area being examined. However, if scanning is performed over an area that is tender or sensitive, you may feel some pressure or minor discomfort from the transducer.

Once the exam is complete, the clear ultrasound gel will be wiped off your skin. Any portions that are not wiped off will dry quickly. The ultrasound gel does not usually stain or discolor clothing.

Typically, ultrasound imaging of the thyroid takes approximately 30 minutes to complete.