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Thyroid Ultrasound

  • A test that uses sound waves to provide images of the thyroid and adjacent structures in the neck
  • The primary purpose is to check for thyroid cancer
  • If a nodules is found, the next step is a fine needle aspiration biopsy to see if it is malignant
  • Involves ultrasound, interventional radiology


If you doctor thinks your thyroid may be enlarged or that your blood work indicates your thyroid gland isn't functioning correctly, a thyroid check may be recommended.

"When physicians feel or see enlarged thyroids in a patient's neck, they often will suggest that patients have an ultrasound performed," says Risa Kent, MD, a diagnostic radiologist at Yale Medicine. 

The primary purpose of the ultrasound is to check for thyroid cancer, and advances in technology have made the test more reliable. “The better our machines get, the better we are at detecting thyroid nodules,” Dr. Kent says. “We are seeing cancers that we would have missed 30 years ago.” 

Earlier detection provides the best opportunity for effective treatment, and Yale Medicine is well equipped to do both.

How do doctors perform thyroid scans?

Doctors use ultrasounds to locate inflammation, nodules and abnormal lymph nodes. "The scan can detect any cause of an enlarged thyroid—one that might explain the symptom the patient mentions such as difficulty swallowing or swelling,” Dr. Kent says.

Ultrasounds are the best tool for the job because they are relatively quick to perform, use no radiation and are more specific than other types of tests such as CT scans or MRIs.

In addition, doctors can display blood flow in the area by using color Doppler, which provides a more detailed picture of the nodules. 

If technicians note an abnormality during the scan, doctors then order a fine needle aspiration biopsy to establish whether a nodule is benign or malignant (cancerous).

The biopsy might require a return visit, though if the radiologist has coordinated with the patient's endocrinologist in advance, it is possible to have the biopsy done at the same time as the ultrasound. 

What is it like for a patient to have a thyroid ultrasound?

A thyroid scan is a simple outpatient procedure. You lie flat on the table, with your head and neck extended. Doctors apply a gel, which allows the sound waves from the ultrasound probe to get through the skin.

If a biopsy is needed, doctors use ultrasound to scan the area again, ensuring that they know exactly where to place the needle. Doctors numb the skin and insert a fine needle right into the nodule to retrieve cells.

Usually three needle passes are performed. After that, they perform one more scan to make sure the needle hasn’t caused any complications, and it rarely does. “We put on a Band-Aid and the patient goes home or right back to work,” Dr, Kent says. “The whole thing takes about a half-hour to an hour.”

Who is at greatest risk for thyroid cancer?

Women are at higher risk than men for thyroid cancer, and the risk increases with age. Anyone with a history of radiation exposure near the neck or a strong family history of thyroid cancer is also considered at risk.

What makes Yale Medicine’s approach to thyroid imaging unique?

Dr. Kent describes the doctors and scientists at Yale Medicine as best in class. "We have a close relationship with endocrinologists and endocrinology surgeons,” she says. “We speak the same language and we learn from each other.”

For the patient, this means that care is streamlined between the doctor who treats the condition and the doctor who interprets the scans, makes a diagnosis and performs a biopsy. This provides a better, safer experience.

Also, a cytology technician is always in the room during a biopsy, in order to look at the biopsy samples under a microscope and ensure that there is enough information to make a definitive diagnosis.