Both 4D color Doppler ultrasound and B-ultrasound belong to the category of color Doppler ultrasound examinations. Simple B-ultrasound examination is the most basic and simplest method of color Doppler ultrasound examination, with a relatively narrow application field. Ultrasound examination, on the basis of general B-ultrasound examination, enhances the examination of blood supply status of the affected area. 4D color Doppler ultrasound examination is a type of ultrasound examination, which is an improvement on the 2D color Doppler ultrasound examination, with enhanced features. The examination results are more vivid and clear, and can be recorded on a video disc.

System B-ultrasound and 4D ultrasound are two different things. System B-ultrasound is a general term for the