Doppler ultrasound

Doppler ultrasonography/Doppler sonography

Also called Doppler ultrasonography or Doppler sonography. It is a painless and bloodless procedure for diagnosis. It measures the rate of blood flow in the vessels.

First of all, gel is spread over the relevant area of skin. This is necessary as any air trapped between the ultrasound probe and the skin would interfere with the examination.

The ultrasound probe sends out ultrasound waves which pass through the skin to reach the blood vessels. If these sound waves hit blood cells in the vessels, some of the waves are reflected back with a different frequency. This change in frequency depends on the movement of the blood cells and thus allows the flow direction and the velocity of the blood cells to be measured. The results can be displayed in various ways, for example, as an audible signal or as the flow rate on a monitor.