Doppler ultrasound is a type of vascular examination, in which the flow of blood in blood vessels (arteries, veins) or heart valves is measured. The flowing blood is made visible and audible by using sound waves. Also, blood pressure is measured in both legs and arms.
Indication
With the aid of Doppler ultrasound, any defects in blood vessels can be detected, such as narrowings, dilations or blockages. This is done in people who have pain in their legs when walking, which is suspected to be caused by a blood vessel narrowing (claudication). This examination is also performed in people with varicose veins or venous leg ulcers.
Working
Doppler ultrasound is done with a probe (taster), the size of a ballpoint pen, and a conductive gel. The sound waves emitted by the probe are reflected by the blood flowing through the arteries. Subsequently, the probe captures the waves again and this signal is made audible and visible by the Doppler device. The sound heard is an amplification of this signal. These waves can be seen on the monitor.
Procedure
First, the blood vessels in the back of the knees, groin and ankles are listened to. The second part of the examination is to measure the blood pressure. Therefore, the patient gets three blood pressure bands to each leg: around the ankles, calves and upper legs and one for each arm. Each band is inflated separately and slowly deflated. The vascular technologist writes down the results of the blood pressure measurement each time. The differences in the measured blood pressures give an impression about the in-between blood vessels, allowing to determine narrowings and blockages in the blood vessels. The Doppler examination is without risk and takes about 30 minutes.
