What Student Need to Know about Color Doppler Ultrasound In Radio Diagnosis.

The use of colour flow Doppler (CFD) or colour Doppler imaging (CDI) (or simply colour Doppler) sonography allows the visualisation of flow direction and velocity within a user defined area. A region of interest is defined by the sonographer, and the Doppler shifts of returning ultrasound waves within are colour-coded based on average velocity and direction. In a manner similar to pulsed wave Doppler (PWD), colour flow Doppler utilises intermittent sampling of ultrasound waves thereby avoiding the range ambiguity characteristic of continuous wave Doppler (CWD). Pulsed wave Doppler, however, is limited to the interrogation of flow velocity and direction along a single line at a certain depth (defined by the sample volume or gate); Colour flow Doppler simultaneously interrogates multiple sample volumes (with each pixel representing a sample volume) along an array of scan lines. Information regarding the flow velocity and direction is arbitrarily colour-coded and rendered onto a grey-scale (or M-mode) imag