There is no CDFI in B-mode ultrasound, it should be CDFI in color ultrasound.The full Chinese name of CDFI refers to color flow Doppler imaging, which is the process of processing the acquired Doppler information, and the color grayscale coding with different colors and brightnesses, respectively, to identify the direction of the blood flow and the magnitude of the velocity, which is superimposed on B-mode ultrasound sonograms. The color represents the direction of blood flow, red represents the blood flow towards the probe, blue represents the blood flow away from the probe, and the brightness of the hue indicates the speed, the brighter the color represents the faster the speed of blood flow, and the darker the color represents the slower the speed of blood flow. At the same time, the color signal is displayed in a way that signifies the attributes of the blood vessels. Color ultrasound has the advantages of two-dimensional ultrasound structural images, and at the same time, it provides rich information on hemodynamics, including the state of blood flow distribution, the direction of blood flow, and the speed of blood flow. Color ultrasound has a wider range of clinical applications than B ultrasound, and has greater clinical application value.