People often ask me online or by phone about “the difference between 3D ultrasound and 4D ultrasound”, so here is a centralized reply. At present, all hospitals in our city use almost the same equipment for mid-pregnancy “teratology examination”. To understand the difference between three-dimensional ultrasound and four-dimensional ultrasound, first of all, we need to briefly understand the difference between physical three-dimensional and four-dimensional: three-dimensional refers to the three-dimensional space we usually talk about, and four-dimensional is the three-dimensional basis plus the time variable. The difference between 3D and 4D ultrasound lies in a “time dimension”, that is to say, 3D ultrasound is a picture and 4D ultrasound is a video. 2. 3D ultrasound and 4D ultrasound images are generated at a later stage, to put it more bluntly, it is like looking at a mirror, you stand still is 3D, you move while looking at it is 4D. 3. In the sense of diagnosis, 3D ultrasound and 4D ultrasound do not have any more advantageous place for diagnosis. For experienced ultrasound doctors, 2-D is sufficient for “teratology examination”. 4.4D ultrasound is dynamic, 3D ultrasound is static, 3D ultrasound is a photo at a certain point of time, 4D ultrasound can be made into a continuous one like DV, and can burn CD. The 3D ultrasound and high-definition 4D ultrasound have the same role of detoxification 5, 4D color ultrasound diagnostic instrument can be dynamic video, made into DV, to add some interest for the family. For ordinary people, this may be the only fun. 6, public hospitals do not promote the reason is very simple: one is to do the risk of teratology examination is too large, the second is the demand is large, time-consuming, do a “teratology examination” takes about 30-40 minutes, where there is time to meet the requirements of carving DV? At present, we need to make an appointment before the 12th week of pregnancy, otherwise we can’t get it at all. 7.