Doppler sonography, or Doppler ultrasound, is a medical imaging technique that uses ultrasound enhanced by the Doppler effect. The Doppler effect generally uses a change in the pitch of sound waves that are measured by an ultrasound-receiving device such as a transducer. Colored Doppler images often provide helpful information about the flow and movement of blood and inner areas of the body. This technique is commonly used during pregnancy to provide detailed images of a developing unborn baby. Other uses for Doppler sonography may include visual examinations of tendons, joints and muscles as well as internal organs.
Pregnant women may undergo an ultrasound for several reasons such as measurement of blood flow through the umbilical cord as well as evaluation of the heart or brain of the unborn baby. This test usually shows the size of a developing fetus and may provide information about the health of the fetus, such as the amount of oxygen received. Physicians may identify health conditions in some pregnant mothers, such as sickle cell anemia or preeclampsia, with the aid of this test.
Some doctors have patients undergo Doppler sonography to investigate a number of medical conditions. Patients with leg pain may have intermittent claudication and atherosclerosis that can appear on a Doppler sonography image in some instances. Varicose veins and other abnormalities of blood vessels can be investigated with this form of ultrasound. Blood clots and blood flow blockages may be identified with Doppler sonography in some cases. Some physicians use this form of ultrasound to provide images that guide their work during surgical procedures such as a blood vessel ablation.
A patient usually lies on his back or side during an ultrasound. Medical professionals normally apply a special Doppler gel to the skin near an area where images are desired. A transducer is typically placed against the gel-covered skin and moved around to get Doppler sonography images from several desired angles. Most Doppler ultrasound tests are completed in 30 to 60 minutes. Doctors may recommend that patients not wear jewelry during a test to reduce the chance of image distortion.
In some instances, patients have unreliable results from a Doppler sonography due to several factors. Patients who do not remain still during the procedure while images are being recorded may cause images to become distorted. In some cases, bones in the body can block the ultrasound signals used during the test. Reliable ultrasound images may be more difficult to obtain in obese individuals, and irregular heart rhythms may cause abnormal images of blood vessels.