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

  • None

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

Publication Review By: the Editorial Staff at Healthcommunities.com

Published: 25 Jan 2012

Last Modified: 09 Mar 2015