Ultrasound scan

What is an ultrasound?

An ultrasound scan is a medical test that uses high-frequency sound waves to capture live images from the inside of your body. It’s also known as sonography.

The technology is similar to that used by sonar and radar, which help the military detect planes and ships. An ultrasound allows your doctor to see problems with organs, vessels, and tissues without needing to make an incision.

Unlike other imaging techniques, ultrasound uses no radiation. For this reason, it’s the preferred method for viewing a developing fetus during pregnancy.Why an ultrasound is performed

Most people associate ultrasound scans with pregnancy. These scans can provide an expectant mother with the first view of her unborn child. However, the test has many other uses.

Your doctor may order an ultrasound if you’re having pain, swelling, or other symptoms that require an internal view of your organs. An ultrasound can provide a view of the:

bladder
brain (in infants)
eyes
gallbladder
kidneys
liver
ovaries
pancreas
spleen
thyroid
testicles
uterus
blood vessels

An ultrasound is also a helpful way to guide surgeons’ movements during certain medical procedures, such as biopsies.

How to prepare for an ultrasound

The steps you will take to prepare for an ultrasound will depend on the area or organ that is being examined.

Your doctor may tell you to fast for eight to 12 hours before your ultrasound, especially if your abdomen is being examined. Undigested food can block the sound waves, making it difficult for the technician to get a clear picture.

For an examination of the gallbladder, liver, pancreas, or spleen, you may be told to eat a fat-free meal the evening before your test and then to fast until the procedure. However, you can continue to drink water and take any medications as instructed. For other examinations, you may be asked to drink a lot of water and to hold your urine so that your bladder is full and better visualized.

Be sure to tell your doctor about any prescription drugs, over-the-counter medications, or herbal supplements that you take before the exam.

It’s important to follow your doctor’s instructions and ask any questions you may have before the procedure.

An ultrasound carries minimal risks. Unlike X-rays or CT scans, ultrasounds use no radiation. For this reason, they are the preferred method for examining a developing fetus during pregnancy.

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