thyroid ultrasound

Thyroid Ultrasound

 

Definition

Thyroid ultrasound is an imaging technique used for diagnosing suspected thyroid disease. It uses harmless, high-frequency sound waves to form an image. The sound waves are reflected by thyroid tissue to form a picture of internal structures. It is not invasive and involves no radiation.

Purpose

The thyroid gland is an organ located in front of the neck. It plays an important role in controlling the body's metabolism. Most thyroid ultrasounds are performed to evaluate a small lump (nodule) in the thyroid found during a physical examination or found by a radionuclide study (thyroid scan). The ultrasound can establish if the nodule is a cyst, which is an abnormal lump that contains fluid, or a solid mass. Cysts are almost always noncancerous (benign), although in some cases the fluid may be taken out for additional testing.
If there are several masses or nodules, this indicates the presence of enlargement of the thyroid gland (goiter). If there is only one mass, it may be cancerous and needs further evaluation. Specialized thyroid ultrasounds, such as color Doppler flow studies, can add valuable information. By showing an image of the blood circulation in the gland, this study can assess some ambiguous masses in greater detail, to further refine diagnosis. In some cases, a needle will be inserted to remove some tissue from the mass for evaluation in a laboratory (needle biopsy). Ultrasound is used during this procedure to help the physician guide the needle to the mass that needs to be evaluated.
Thyroid ultrasound can measure the size of the thyroid with great precision. Ultrasound studies may be done periodically to assess the response of the thyroid gland to medical therapy. An enlarged gland or a benign nodule should decrease in size when appropriate thyroid medication is taken.
Patients who have received therapeutic radiation to the head or neck may be monitored at regular intervals using thyroid ultrasound. The radiation puts these patients at higher risk for developing thyroid cancer or other abnormalities. In the early stages, these conditions may not cause symptoms or be apparent during a physical examination. They can, however, be detected by ultrasound.
Certain invasive medical procedures may be performed under ultrasound guidance. This is because ultrasound allows the physician to observe a needle as it enters body tissue below the skin. This is useful to direct the removal of fluid from a cyst (aspiration) or needle biopsy. Medications to treat recurrent cysts may be administered directly to the area using ultrasound guidance.

Precautions

Thyroid ultrasound is safe for people of all ages. It is the preferred procedure to evaluate suspected disease in pregnant women because no radiation is involved.

Description

The study may be done in an outpatient facility or in a hospital department. The patient lies on his or her back. A pillow or rolled towel is placed under the shoulders and upper back, allowing the head to tilt back (hyperextend). A gel that enhances sound transmission is spread over the thyroid area. The technologist then gently places a transducer, an instrument about the size of an electric shaver, against the skin. It is moved over the thyroid area. The images from reflected sound waves appear on a monitor screen. There is no discomfort involved with this study. The examination takes 15-30 minutes.

Preparation

Some facilities recommend limiting food and drink for one hour before the study to prevent discomfort. No other preparation is needed.

Aftercare

No special restrictions or procedures are needed after a thyroid ultrasound.

Risks

There are no risks with this procedure.

Normal results

A normal study would reveal a thyroid gland of normal size, shape, position, and uniform texture.

Abnormal results

A thyroid ultrasound may reveal cysts, solid masses that may or may not be cancerous, or an enlarged thyroid gland (goiter). In many cases, the ultrasound can establish a diagnosis. Sometimes the information revealed will need to be combined with data from other studies to determine the problem.

Resources

Periodicals

Rifat, Sami F., and Mack T. Ruffin. "Management of ThyroidNodules." American Family Physician 50 (September 15, 1994): 785-791.

thyroid ultrasound

an ultrasound examination of the thyroid gland, used to distinguish cystic from solid thyroid nodules, to determine the efficacy of treatment of a thyroid mass, and to study the thyroid gland of pregnant patients.
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References in periodicals archive ?
If an enlarged thyroid gland is suspected, a thyroid ultrasound can be done at any time.
Thyroid ultrasound features associated with malignancy in thyroid nodules are microcalcifications, hypoechogenicity, irregular margins or absent halo sign, solid areas, intranodular vascularisation.
The patient had been followed by her endocrinologist for hypothyroidism, and a recent thyroid ultrasound had revealed a 1-cm hypoechoic right thyroid nodule.
Tariq Mahmood remarked that in Pakistan it is the radiologists who mostly do the Thyroid ultrasound and write reports.
Patient was layed his on back, a rolled towel was placed below shoulders and upper back and head was tilted in hyper extended position for thyroid ultrasound.
In 2009, the American Thyroid Association guidelines for the management of thyroid nodules and DTC advised that upon the detection of a thyroid nodule, every patient should undergo a complete history and physical examination focusing on the thyroid gland, measurement of serum thyroid stimulating hormone (TSH) with radionuclide scan if the value is below normal, and thyroid ultrasound to assess sonographic features, as well to determine the presence of additional nodules and lymphadenopathy, with the subsequent performance of a fine-needle aspiration biopsy (FNAB), as indicated (3).
s thyroid ultrasound revealed a moderately enlarged thyroid.
A prospective study of thyroid ultrasound scan in the clinically solitary thyroid nodule.
Objective: To determine the diagnostic validity of thyroid ultrasound in differentiating between benign and malignant thyroid nodules.
Only one study comes close; Thyroid Ultrasound Findings in Children from Three Japanese Prefectures: Aomori, Yamanaski and Nagasaki, published last December in PLOS One, an international peer-reviewed online science publication.
Thyroid Ultrasound when compared to other modalities is a more accurate non
In a retrospective analysis of 223 patients with nodular thyroid disease, thyroid ultrasound altered clinical management of 63% of patients with abnormal thyroid exams.