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|What is an Ultrasound?
Ultrasound is a procedure that uses high-frequency sound waves to view internal organs and produce images of the human body. The human ear cannot hear the sound waves used in an ultrasound. Ultrasound is:
Ultrasound imaging, also called ultrasound scanning, involves exposing part of the body to high-frequency sound waves to produce pictures of the inside of the body. Ultrasound exams do not use ionizing radiation (as used in x-rays). Because ultrasound images are captured in real-time, they can show the structure and movement of the body's internal organs, as well as blood flowing through blood vessels.
Conventional ultrasound displays the images in thin, flat sections of the body. Advancements in ultrasound technology include three-dimensional (3-D) ultrasound that formats the sound wave data into 3-D images. A Doppler ultrasound study may be part of an ultrasound examination.
Doppler ultrasound is a special ultrasound technique that evaluates blood velocity as it flows through a blood vessel, including the body's major arteries and veins in the abdomen, arms, legs and neck.
How should I prepare?
You should wear comfortable, loose-fitting clothing for your ultrasound exam. You may need to remove all clothing and jewelry in the area to be examined.
You may be asked to wear a gown during the procedure.
Other preparation depends on the type of examination you will have. For some scans your doctor may instruct you not to eat or drink for as many as 12 hours before your appointment. For others you may be asked to drink up to six glasses of water two hours prior to your exam and avoid urinating so that your bladder is full when the scan begins.
What will I experience during and after the procedure?
Most ultrasound examinations are painless, fast and easy.
After you are positioned on the examination table, the sonographer will apply some warm water-based gel on your skin and then place the transducer firmly against your body, moving it back and forth over the area of interest until the desired images are captured. There is usually no discomfort from pressure as the transducer is pressed against the area being examined.
If scanning is performed over an area of tenderness, you may feel pressure or minor pain from the transducer.
Ultrasound exams in which the transducer is inserted into an opening of the body may produce minimal discomfort.
If a Doppler ultrasound study is performed, you may actually hear pulse-like sounds that change in pitch as the blood flow is monitored and measured.
Once the imaging is complete, the gel will be wiped off your skin.
After an ultrasound exam, you should be able to resume your normal activities within a few hours.
What are some common uses of the procedure?
Ultrasound examinations can help to diagnose a variety of conditions and to assess organ damage following illness.
Ultrasound is used to help physicians evaluate symptoms such as:
Ultrasound is a useful way of examining many of the body's internal organs, including but not limited to the:
Doppler ultrasound images can help the physician to see and evaluate:
How does the procedure work?
When a sound wave strikes an object, it bounces back, or echoes. By measuring these echo waves it is possible to determine how far away the object is and its size, shape, and consistency (whether the object is solid, filled with fluid or both).
Doppler ultrasound, a special application of ultrasound, measures the direction and speed of blood cells as they move through vessels. The movement of blood cells causes a change in pitch of the reflected sound waves (called the Doppler effect). A computer collects and processes the sounds and creates graphs or color pictures that represent the flow of blood through the blood vessels.
A clear water-based gel is applied to the area of the body being studied to help the transducer make secure contact with the body and eliminate air pockets between the transducer and the skin. The sonographer (ultrasound technologist) then presses the transducer firmly against the skin and sweeps it over the area of interest.
Who interprets the results and how do I get them?
A radiologist, a physician specifically trained to supervise and interpret radiology examinations, will analyze the images and send a signed report to your primary care physician or the physician who referred you for the exam, who will share the results with you.
What are the benefits vs. risks?