An ultrasound of the thyroid produces a picture of the thyroid gland.
The patient is positioned lying face-up on an examination table that can be tilted or moved.
A clear water-based gel is applied to the area of the body being studied to help the transducer make secure contact with the body and eliminate air pockets between the transducer and the skin. The sonographer or radiologist then presses the transducer firmly against the skin and sweeps it over the area of interest.
This ultrasound examination is usually completed within 15 minutes.
The thyroid gland is located in front of the neck just below the Adam's apple and is shaped like a butterfly, with two lobes on either side of the neck connected by a narrow band of tissue. It is one of nine endocrine glands located throughout the body that make and send hormones into the bloodstream.
An ultrasound of the thyroid is typically used to help diagnose:
- a lump in the thyroid.
- a thyroid that is not functioning properly.
Because ultrasound provides real-time images, it also can be used to guide procedures such as needle biopsies, in which needles are used to extract sample cells from an abnormal area for laboratory testing.
What are the limitations of an Ultrasound of the Thyroid?
If a lump is detected on ultrasound within the thyroid gland, it is common that the radiologist/sonographer cannot distinguish between benign and malignant lumps with complete certainty. A fine needle biopsy and review of tissue under a microscope is often necessary, while in some cases surveillance and a repeat sonogram after a few months looking for stability may suffice.
It is not possible to determine thyroid function—that is, whether the thyroid gland is underactive, overactive, or normal—with ultrasound. For that determination, your doctor may order a blood test or a radioactive iodine uptake test.