Colour Doppler

Doppler ultrasound is a medical imaging technique used to visualize the movement of blood in vessels. It is based on the Doppler effect, the change in frequency of a waveform caused by the relative motion of the source and observer. In medical ultrasonography, it is used to assess blood flow in arteries and veins, as well as fetal circulation. Colour Doppler adds information about the direction and velocity of blood flow by displaying different colours depending on the speed of flow. This can be used to create images called colour maps or power doppler spectra.