Ultrasound scans how does it work

Some imaging tests and treatments have special pediatric considerations. The teddy bear denotes child-specific content. Please contact your physician with specific medical questions or for a referral to a radiologist or other physician. To locate a medical imaging or radiation oncology provider in your community, you can search the ACR-accredited facilities database.

This website does not provide cost information. The costs for specific medical imaging tests, treatments and procedures may vary by geographic region. Web page review process: This Web page is reviewed regularly by a physician with expertise in the medical area presented and is further reviewed by committees from the Radiological Society of North America RSNA and the American College of Radiology ACR , comprising physicians with expertise in several radiologic areas.

Outside links: For the convenience of our users, RadiologyInfo. Toggle navigation. What is General Ultrasound Imaging? What are some common uses of the procedure? How should I prepare?

What does the equipment look like? How does the procedure work? How is the procedure performed? What will I experience during and after the procedure? Who interprets the results and how do I get them? What are the benefits vs.

What are the limitations of General Ultrasound Imaging? A Doppler ultrasound study may be part of an ultrasound examination. There are three types of Doppler ultrasound: Color Doppler uses a computer to convert Doppler measurements into an array of colors to show the speed and direction of blood flow through a blood vessel.

Power Doppler is a newer technique that is more sensitive than color Doppler and capable of providing greater detail of blood flow, especially when blood flow is little or minimal.

Power Doppler, however, does not help the radiologist determine the direction of blood flow, which may be important in some situations.

Spectral Doppler displays blood flow measurements graphically, in terms of the distance traveled per unit of time, rather than as a color picture. It can also convert blood flow information into a distinctive sound that can be heard with every heartbeat. Doctors use ultrasound to evaluate : pain swelling infection Ultrasound is a useful way of examining many of the body's internal organs, including but not limited to the: heart and blood vessels, including the abdominal aorta and its major branches liver gallbladder spleen pancreas kidneys bladder uterus , ovaries , and unborn child fetus in pregnant patients eyes thyroid and parathyroid glands scrotum testicles brain in infants hips in infants spine in infants Ultrasound is also used to: guide procedures such as needle biopsies , in which needles remove cells from an abnormal area for laboratory testing.

Ultrasound of the heart is commonly called an "echocardiogram" or "echo" for short. Doppler ultrasound helps the doctor to see and evaluate: blockages to blood flow such as clots narrowing of vessels tumors and congenital vascular malformations reduced or absent blood flow to various organs, such as the testes or ovary increased blood flow, which may be a sign of infection With knowledge about the speed and volume of blood flow gained from a Doppler ultrasound image, the doctor can often determine whether a patient is a good candidate for a procedure like angioplasty.

You may need to change into a gown for the procedure. Doctors perform Doppler sonography with the same transducer. These exams include: Transesophageal echocardiogram. The doctor inserts the probe into the esophagus to obtain images of the heart. Transrectal ultrasound. The doctor inserts the probe into a man's rectum to view the prostate.

Transvaginal ultrasound. The doctor inserts the probe into a woman's vagina to view the uterus and ovaries.

Most ultrasound exams are painless, fast, and easily tolerated. Ultrasound exams that insert the transducer into a body cavity may produce minimal discomfort. Most ultrasound exams take about 30 minutes. More extensive exams may take up to an hour. After an ultrasound exam, you should be able to resume your normal activities immediately.

Benefits Most ultrasound scanning is noninvasive no needles or injections. Occasionally, an ultrasound exam may be temporarily uncomfortable, but it should not be painful. Ultrasound is widely available, easy to use, and less expensive than most other imaging methods. Ultrasound imaging is extremely safe and does not use radiation.

Ultrasound scanning gives a clear picture of soft tissues that do not show up well on x-ray images. Ultrasound is the preferred imaging modality for the diagnosis and monitoring of pregnant women and their unborn babies. Other conditions detected by an ultrasound scan, such as abdominal masses, may need further tests or exploratory surgery.

This page has been produced in consultation with and approved by:. Allergy testing is used to find which substances provoke an allergic reaction. Barium tests are used to examine conditions of the digestive tract such as reflux, narrowing or ulceration. Before a biopsy, you need to discuss a range of issues with your doctor or surgeon.

Pathology tests cover blood tests, and tests on urine, stools faeces and bodily tissues. The full blood count FBC test looks for abnormalities in the blood, such as unusually high or low numbers of blood cells. Content on this website is provided for information purposes only. Information about a therapy, service, product or treatment does not in any way endorse or support such therapy, service, product or treatment and is not intended to replace advice from your doctor or other registered health professional.

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Skip to main content. Medical tests. Home Medical tests. Ultrasound scan. Actions for this page Listen Print. Summary Read the full fact sheet. On this page. Its small size and low cost, as well as range of applications, allow it to be used in ambulances, emergency rooms, field hospitals, or other remote locations.

It is currently being used in more than 60 countries around the world. Vscan image on right courtesy of Kai Thomenius, Ph. Histotripsy technique for dissolving blood clots. Researchers at the University of Michigan are investigating the clot-dissolving capabilities of a high intensity ultrasound technique, called histotripsy, for the non-invasive treatment of deep-vein thrombosis DVT. This technique uses short, high-intensity pulses of ultrasound to cause clot breakdown.

The researchers have successfully demonstrated the effectiveness of this technique in pigs and its possible use in humans. They are currently working on new methods to avoid inadvertent vessel damage during clot treatment, and to provide real-time imaging feedback to monitor the treatment. This research could have a significant impact, since current conventional treatments for DVT involve drug therapy and sometimes invasive removal of the clots, which requires a several-day hospital stay, and may result in complications after treatment.

In contrast, the non-invasive histotripsy technique is 50 times faster than the current technique, does not require drugs or external agents, and if successful, could be used as an outpatient procedure. How does it work? What is ultrasound used for? Are there risks? What is medical ultrasound? Diagnostic ultrasound is a non-invasive diagnostic technique used to image inside the body. Ultrasound probes, called transducers, produce sound waves that have frequencies above the threshold of human hearing above 20KHz , but most transducers in current use operate at much higher frequencies in the megahertz MHz range.

Most diagnostic ultrasound probes are placed on the skin. However, to optimize image quality, probes may be placed inside the body via the gastrointestinal tract, vagina, or blood vessels.

In addition, ultrasound is sometimes used during surgery by placing a sterile probe into the area being operated on. Source: Terese Winslow Ultrasound waves are produced by a transducer, which can both emit ultrasound waves, as well as detect the ultrasound echoes reflected back.

An ultrasound transducer. The ultrasound probe transducer is placed over the carotid artery top. A color ultrasound image bottom, left shows blood flow the red color in the image in the carotid artery. Waveform image bottom right shows the sound of flowing blood in the carotid artery.

Click here to watch video Ultrasound color Doppler shows a clot blocking blood flow in a pig. Source: Zhen Xu, Ph. Source: Zhehn Xu, Ph. Reviewed July