What is the difference between a CT scan and an MRI?

Both a CT scan and an MRI create detailed pictures of the inside of your body, but they work differently.

A CT scan uses an X-ray machine linked to a computer to take pictures from many angles, which are combined into 3-D images. An MRI uses a powerful magnet and radio waves — not radiation — to take pictures of the body in slices.

Because they work differently, each is better suited to certain questions. Your doctor chooses the scan that will best answer the question at hand, and sometimes both are used.