Patient Information - Thyroid Exam

What You Should Know About Your Ultrasound Examination
Your doctor has requested an ultrasound examination of your thyroid...you may have heard about ultrasound examinations (sonograms), but you still may have unanswered questions. The American Institute of Ultrasound in Medicine (AIUM)-an organization of doctors, sonographers, and scientists-has put together information to help answer some of the most commonly asked questions.

What Is Ultrasound?
Ultrasound is like ordinary sound except it has a frequency (or pitch) higher than human beings can hear. When sent into your body from a device called a transducer resting on your neck, the sound echoes back from the organs inside your body. These returning echoes are changed by a computer into a picture. These pictures can be recorded on film, paper, videotape, or computer. During your thyroid ultrasound examination, ultrasound will produce pictures of your thyroid gland, including its size, shape, and blood vessels. The ultrasound will reveal any nodules (lumps) or cysts (lumps with fluid) that may be present in your thyroid gland. An ultrasound examination is commonly called the practice of sonography, but also may be referred to as diagnostic ultrasound imaging.

What Is the Thyroid?
The thyroid is a butterfly-shaped gland that wraps around the front part of your neck just below your Adam's apple. The thyroid makes hormones that help control your body's metabolism. The hormone produced by the thyroid has an effect on almost every tissue and cell in your body.

What Does the Thyroid Do?
The thyroid operates as part of a feedback loop involving body parts called the hypothalamus and the pituitary gland. First, the hypothalamus sends a signal to your pituitary gland through a hormone called TRH. When your pituitary gland receives this signal, it releases another hormone called TSH to your thyroid gland. Upon receiving TSH, your thyroid releases 2 of its own hormones (T3 and T4), which then enter your bloodstream and affect the metabolism of your heart, liver, muscles, and other organs. Finally, your pituitary gland monitors the level of thyroid hormone in your blood and increases or decreases the amount of TSH released, which then changes the amount of thyroid hormone in your blood.

Why Should I Have a Thyroid Ultrasound Exam?
There are many reasons for examining the thyroid with ultrasound. The most common reason is to provide more information for your doctor

about a mass your doctor felt while examining you;
after something unusual was found by other exams, such as a nuclear scan, a CT scan, or an MRI exam;
about what caused your thyroid gland to get larger;
about what caused the pain or swelling in your thyroid gland; or
about abnormalities in your thyroid, such as masses or cysts.

A sonogram may not provide all the information your doctor needs. In these cases, more studies or tests may be needed. These may include blood tests; a biopsy in which your doctor removes a small amount of cells or fluid; or other types of ultrasound examinations.

Who Will Perform the Examination?
In most cases, a sonographer, who is a professional trained to conduct ultrasound examinations, will perform the exam. He or she obtains and records a series of pictures. A doctor then reviews the pictures. The doctor may discuss your exam with the sonographer, and will then give your own doctor an official explanation or interpretation of what was seen on the sonogram. This interpretation may not be available immediately after you have your exam. In some cases, the doctor also will examine you to confirm or resolve uncertain or unclear findings.

Are There Any Special Preparations for the Examination?
There is no special preparation for this examination. For your convenience, you should wear a top that can be removed easily during the ultrasound examination. The room is usually darkened during the examination to make it easier for the sonographer or doctor to see the pictures on the computer screen. After the examination, you may safely drive home and eat and drink normally.

Will It Hurt?
There is no pain involved in an ultrasound examination of the thyroid. The transducer is placed on your skin surface after a gel is applied to your neck to provide better contact. The gel may feel cool and may temporarily leave a mark on your clothes, so you may want to wear easily washable clothing. However, the gel usually dries to a white powder that can be brushed off.

How Long Will It Take?
The length of time for the examination will depend on the specific reasons your doctor requested it. The reasons will affect how complex the examination needs to be.

Is Ultrasound Safe?
There are no known harmful effects linked to the medical use of ultrasound. Although the possibility exists that harmful effects may be identified in the future, current information indicates that the benefits to patients far outweigh the risks, if any, that may be present.

What Are the Limitations of the Examination?
It may be difficult for a sonographer or doctor to obtain the desired pictures if you have a short or thick neck. Also, if there are multiple nodules or cysts, it can be difficult for the doctor to see each one individually. An ultrasound examination of the thyroid cannot determine the exact cause of a nodule; however, there are characteristics of the image that can help the doctor determine if there is a high chance of cancer (malignant) or a low chance of cancer (benign). Your doctor may recommend further tests, such as an ultrasound-guided biopsy or a fine-needle aspiration. Finally, the quality of the ultrasound examination also depends on the examiner's experience and the type of equipment used.

How Much Does the Exam Cost?
The price of an ultrasound examination varies widely depending on a variety of factors, including the reason for the examination and the type of equipment used. Generally, insurance companies will help cover the cost of ultrasound examinations of the thyroid requested by your doctor.

Last updated April 2004