Both 3D ultrasound and 4D ultrasound use sound waves to create sonographic images, most commonly of a developing fetus in the womb. The main difference between the two is in the level of detail and the way the images are presented.
3D ultrasound creates a three-dimensional image of the baby. It is a static image, meaning it is a snapshot of the baby at a particular moment in time. The image is created by combining multiple 2D images taken from different angles to create a 3D image. This type of ultrasound provides a more detailed view of the baby's features, such as the face, limbs, and organs.
4D ultrasound, on the other hand, creates a moving, real-time video of the baby in 3D. This means that the image shows the baby moving and the user can see the baby’s movements in real-time. 4D ultrasound is a more advanced technology than 3D, but it has a lower level of detail than 3D. 4D is useful when trying to image an active baby.
In summary, the main difference between 3D ultrasound and 4D ultrasound is that 3D ultrasound produces a static, three-dimensional image of the baby, while 4D ultrasound creates a moving, real-time video of the baby in 3D.