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). 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.