Color Doppler is detection and finding motion of blood flow using a Color map that is incorporated standard format B-mode image .It detects and interrogated large scale of region and blood flow, typically blue and red. It can also detected whether the blood moving toward or way from the transducer.It has estimated frequency shift at each point at which motion is detected within an interrogated region, thus yielding information on direction of motion and velocity.
Shades of color blue and red used to reflect relative velocity of blood flow. All stationary objects showing in gray scale as a B-mode imaging. The benefit of color Doppler is that information on the direction and relative Velocity of blood flow can be obtained. Color Doppler is limited by its dependence on the relative angle of the transducer to the blood flow.