Ultrasound & Doppler
What is an ultrasound?
An ultrasound is an imaging test that uses sound waves to create a picture (also known as a sonogram) of organs, tissues, and other structures inside the body. Unlike x-rays, ultrasounds don’t use any radiation. An ultrasound can also show parts of the body in motion, such as a heart beating or blood flowing through blood vessels.
There are two main categories of ultrasounds: pregnancy ultrasound and diagnostic ultrasound.
Pregnancy ultrasound is used to look at an unborn baby. The test can provide information about a baby’s growth, development, and overall health.
Diagnostic ultrasound is used to view and provide information about other internal parts of the body. These include the heart, blood vessels, liver, bladder, kidneys, and female reproductive organs.
Other names: sonogram, ultrasonography, pregnancy sonography, fetal ultrasound, obstetric ultrasound, diagnostic medical sonography, diagnostic medical ultrasound
What is it used for?
An ultrasound can be used in different ways, depending on the type of ultrasound and which part of the body is being checked.
A pregnancy ultrasound is done to get information about the health of an unborn baby. It may be used to:
- Confirm that you are pregnant.
- Check the size and position of the unborn baby.
- Check to see you are pregnant with more than one baby.
- Estimate how long you have been pregnant. This is known as gestational age.
- Check for signs of Down syndrome, which include thickening in the back of the baby's neck.
- Check for birth defects in the brain, spinal cord, heart, or other parts of the body.
- Check the amount of amniotic fluid. Amniotic fluid is a clear liquid that surrounds an unborn baby during pregnancy. It protects the baby from outside injury and cold. It also helps promote lung development and bone growth.
Diagnostic ultrasound may be used to:
- Find out if blood is flowing at a normal rate and level.
- See if there is a problem with the structure of your heart.
- Look for blockages in the gallbladder.
- Check the thyroid gland for cancer or non-cancerous growths.
- Check for abnormalities in the abdomen and kidneys.
- Help guide a biopsy procedure. A biopsy is a procedure that removes a small sample of tissue for testing.
In women, diagnostic ultrasound may be used to:
- Look at a breast lump to see if it might be cancer. (The test may also be used to check for breast cancer in men, though this type of cancer is far more common in women.)
- Help find the cause of pelvic pain.
- Help find the cause of abnormal menstrual bleeding.
- Help diagnose infertility or monitor infertility treatments.
In men, diagnostic ultrasound may be used to help diagnose disorders of the prostate gland.
What is an Doppler?
A Doppler ultrasound is a noninvasive test that can be used to estimate the blood flow through your blood vessels by bouncing high-frequency sound waves (ultrasound) off circulating red blood cells. A regular ultrasound uses sound waves to produce images, but can't show blood flow.
A Doppler ultrasound may help diagnose many conditions, including:
- Blood clots
- Poorly functioning valves in your leg veins, which can cause blood or other fluids to pool in your legs (venous insufficiency)
- Heart valve defects and congenital heart disease
- A blocked artery (arterial occlusion)
- Decreased blood circulation into your legs (peripheral artery disease)
- Bulging arteries (aneurysms)
- Narrowing of an artery, such as in your neck (carotid artery stenosis)
A Doppler ultrasound can estimate how fast blood flows by measuring the rate of change in its pitch (frequency). During a Doppler ultrasound, a technician trained in ultrasound imaging (sonographer) presses a small hand-held device (transducer), about the size of a bar of soap, against your skin over the area of your body being examined, moving from one area to another as necessary.
This test may be done as an alternative to more-invasive procedures, such as angiography, which involves injecting dye into the blood vessels so that they show up clearly on X-ray images.
A Doppler ultrasound test may also help your doctor check for injuries to your arteries or to monitor certain treatments to your veins and arteries.
