What are 2D, 3D, and 4D ultrasounds?

Ultrasound is a way to look inside the body with high-frequency sound waves. It works just like the sonar on boats, which use sound waves to locate things underwater. The ultrasound machines used for medical imaging use waves between 2 to 20 megahertz – that’s about 100 times higher than the top of the range we’re able to hear (20 to 20,000 hertz). The waves bounce off tissues to create a picture on a screen. That picture is called a sonogram.

  • 2D ultrasound is the standard ultrasound that healthcare providers use. This process creates simple, black-and-white images that create a cross-section view, with bright spots for denser materials like bone.
  • 3D ultrasound uses the same basic idea as 2D ultrasound, but takes many images from different angles and processes them together to create an image that looks like a real photograph.
  • 4D ultrasound adds a fourth dimension – time. In a 4D ultrasound, a series of 3D images is put together to form a low-resolution video.