A device called a transducer is passed over your neck, directing high-frequency sound waves (ultrasound) at the thyroid gland. The sound waves are reflected back to the transducer and electronically converted into images displayed on a viewing monitor. The images are then saved on film or video and reviewed for abnormalities. Thyroid ultrasound is most often done when a thyroid growth, or nodule, is detected on another imaging test or by palpating the gland.
Purpose of the Thyroid Ultrasound
- To help diagnose a thyroid that is not functioning properly
- To help diagnose a lump in the thyroid and determine whether a thyroid nodule is a fluid-filled cyst or a solid tumor; cysts are usually benign, while tumors may be malignant (cancerous)
- To monitor the size and condition of a thyroid nodule during treatment
- To monitor thyroid cancer patients for cancer recurrence after treatment or cancer spread to the lymph nodes
- To detect a thyroid lesion that cannot be felt upon examination in a patient exposed to therapeutic irradiation
- To identify ultrasonic thyroid patterns consistent with diagnoses such as thyroiditis
- To deliver medication or high-energy therapy precisely into a lesion, sparing surrounding tissue
- To monitor the thyroid in-utero for size, ultrasonic texture and vascularity
- To assess size and location of the thyroid in newborn babies
- To screen thyroids during an epidemiologic investigation
Who Performs Thyroid Ultrasound
- A doctor or a technician who is trained in ultrasonography
Special Concerns about Thyroid Ultrasound
Before the Thyroid Ultrasound
- Wear comfortable, loose-fitting clothing.
- You may need to wear a hospital gown during the procedure and remove jewelry.
- No other preparation is required.
What You Experience during Thyroid Ultrasound
- You will lie on your back on an examination table.
- A pillow is placed under your shoulder blades to push the neck forward.
- A water-soluble gel is applied to the skin on your neck to enhance sound wave transmission.
- The examiner then moves the transducer back and forth over your neck to obtain different views of the thyroid.
- Once clear images are obtained, they are recorded on film or video for later analysis.
- The test takes about 15 to 30 minutes.
Risks and Complications
- Ultrasound is painless, noninvasive, and involves no exposure to radiation. There are no associated risks.
After the Thyroid Ultrasound
- The examiner removes the conductive gel from your skin.
- You are free to resume your normal diet and activities.
Results of Thyroid Ultrasound
- A radiologist reviews the recorded images and video for evidence of abnormalities.
- If a thyroid nodule is found to be a fluid-filled cyst, it can be aspirated (drained) with a needle.
- If the mass is mixed or solid, a tumor may be present. A fine needle aspiration biopsy is usually required to establish a definitive diagnosis.
The Johns Hopkins Consumer Guide to Medical Tests
Simeon Margolis, M.D., Ph.D., Medical Editor
Updated by Remedy Health Media