A Doppler test uses ultrasonic waves to assess the movement of blood through the blood vessels. It is used as a preventative measure for conditions such as stroke. The Doppler test usually used on the major veins and arteries of the legs, arms and neck. It is also used to locate blood clots that, if they break loose, can be fatal.
During a Doppler test, a device is held over the skin. This device sends and picks up sound waves. The movement of the blood causes changes in pitch. However, when the blood is not moving, this pitch does not change. When there is something solid in the bloodstream, such as a blood clot, the sound wave will bounce off of it. This information is fed into a computer, which then prints a photo or a graph.
There are four types of Doppler tests. The continuous wave Doppler checks for the changes in pitch. This type is done via a portable machine and can produce quick results. The Duplex Doppler produces a picture of not only the blood vessels but organs surrounding the test site. The Color Doppler produces a picture of the speed and direction of the blood flow. The newest test is the Power Doppler which is the most powerful. It produces photos of bloods vessels inside of organs.
Besides blockages in the blood vessels, a Doppler test can be used to tell a pregnant mother about the health of her baby, such as the blood flow in the placenta and umbilical cord. It is also used to evaluate varicose veins, check levels of arterial plaque and monitor people have already had a stroke. Doppler tests are also commonly used for people afflicted with sickle-cell anemia.
Your physician will ask you to abstain from nicotine use for a few hours before the test since nicotine causes the constriction of blood vessels and may mar test results. A Doppler is performed by a radiologist or a sonographer. The doctor will usually ask you to remove most of your clothes for the test. The doctor will apply gel to the area of the body they are examining. The test usually lasts a half hour to an hour.
Though there are no risks associated with the Doppler test, there are some factors that may cause inaccurate results. Bones near the area being tested or excess gas in the intestinal tract might interfere with results. Also people who are obese, unable to sit still or have heart rhythm issues may also give you a result that is not entirely accurate.