Thyroid ultrasound (US) imaging, thyroid US scanning, thyroid ultrasonography or sonography
Ultrasound scans are high frequency sound waves too high for humans to hear. After the Titanic hit an iceberg and sank in 1912, scientists researched ways to find underwater icebergs. During this time, SONAR (sound navigation and ranging), which uses ultrasound, was developed.
Ultrasound waves sent to the part of the body being examined are reflected, refracted, or absorbed at the interfaces inside the body. Echoes that return in this way carry information about the size, distance, and uniformity of internal organs. This is displayed on a monitor to create an ultrasound image.
During thyroid sonography, a hand-held device called a "transducer" is placed on the area being examined and moved around. This transducer generates ultrasound and sends it through the body. It also detects the returning echoes and transmits them as electrical signals. Because one transducer continuously generates many ultrasound waves while detecting echoes, a real time image can be produced on a viewing monitor. These images can be recorded on videotape, or images can be frozen and recorded on to film.
Plenty of lubricating gel is applied on the skin during thyroid sonography so that the transducer can be moved around to produce real time images. Ultrasound is similar to audible sound in that it can pass through water and human organs easily, but it can't pass through air or bone. So gel is applied between the transducer and the skin to bridge the gap, and effectively send the ultrasound waves.
Because US images are real time images, blood flow, blood vessels, and the movement of internal organs from breathing can be seen.
Safe, painless, easy, fast, and widely available
Real time imaging -- ultrasonography can be used to guide invasive procedures such as biopsy, and to visualize moving organs such as blood vessels, the esophagus, and blood flow.
In case of an emergency, bedside sonography can be done without particular patient preparations.
Pain in the anterior neck
Swelling in the anterior neck
Symptoms of abnormal thyroid hormone:
Symptoms of abnormal parathyroid hormone:
- Hypothyroidism -- fatigue, cold intolerance, weakness, depression, hair thinning, weight gain, muscle cramps
- Hyperthyroidism -- nervousness, inability to sleep, tremors, sweating, heat intolerance, weight loss, palpitation
To guide invasive procedures -- needle biopsy (i.e., thyroid cancer), sampling or withdrawal of fluid (abscess, cyst)
- Hypoparathyroidism -- muscle spasm, irritability, lack of energy
- Hyperparathyroidism -- kidney stone, weight loss, muscle weakness, numbness
Cysts of the thyroid
Tumors of thyroid (such as adenoma) and parathyroid
Cancer of the thyroid and parathyroid
Congenital mass in the thyroid gland/anterior neck -- thyroglossal duct cyst, branchial cleft cyst
Goiter (enlarged thyroid)
Enlarged lymph nodes around thyroid
Multiple endocrine neoplasia
You may be asked to remove your clothing and necklace, and put on a hospital gown.
You will be lying down on an examination table with your neck hyper extended.
A lubricating gel is applied to your neck.
An apparatus known as a transducer is placed on the neck area and moved around to get real time images.
After the examination, the gel is cleaned off and you can change back into your clothes.
Examinations usually take 10-30 minutes.
No special preparation is needed.
You should wear comfortable, loose-fitting clothing.
You may need to take off you clothes and jewelry, and put on a hospital gown.
Tell the sonographer, sonologist, or physician sonologist conducting the examination about any pain, bleeding, or any other symptoms you might have. Also, telling the examiner about past ultrasounds and surgeries is helpful, and sometimes it is crucial information.
The image recorded on film or videotape is interpreted and analyzed by a radiologist (a physician specialist experienced in ultrasound and other radiology examinations). The official report is sent to the practitioner who requested the examination.
Your personal physician's office will inform you when the results are in, and what they mean. The doctor will use the results as a reference in evaluating and treating you.
There is no known risk to humans relating to diagnostic ultrasound.
Unlike X-ray examinations, ultrasound does not use radiation. Pregnant women and fetuses can be examined safely.
Ultrasound does not penetrate air or bone. So if an abnormal part is behind the trachea (wind pipe), spine, clavicle, sternum, or ribs, it may not be discovered. When the thyroid gland becomes enlarged or thyroid cancer leads to a thoracic cavity, it is difficult to evaluate the whole mass because it is obstructed by bone. In this case, a CT scan or an MRI must also be taken. To evaluate bone lesions, other imaging modalities (X-ray, CT scan, MRI, radioisotope scan) should be done.
Ultrasonography is an operator-dependent, subjective test. So the more experience the operator has, the better the patient listens to the operator's instructions. And the more the operator knows about the patient's past medical history, current medical history, and the results of other radiological and laboratory tests, the better the examination will be. So, before you take ultrasonography, ask if the practice where your scan is being performed is accredited either by the American Institute of Ultrasound in Medicine or the American College of Radiology.