Doctor Decoded: CT Scan vs. MRI

Learn the difference between CT scans and MRIs, including the type of energy they use and what they’re used for.

Written by Lauren Smith, MA | Reviewed by Alexandra Schwarz, MD

Updated on August 31, 2023

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CT scan stands for computed tomography scan. Like an X-ray, it uses radiation to create the image. However, CT scans are much more detailed than an X-ray, and they can create cross-sectional, 360-degree views of the body’s structures. That’s because the X-ray beam of a CT scan moves in a circle around the body.

MRI stands for magnetic resonance imaging. Unlike a CT scan or X-ray, MRIs use a large, powerful magnet to create the images—not radiation. Essentially, the body’s protons react to the magnetic field, which creates signals that are picked up by the MRI receiver.

CT scans and MRIs have a few things in common. Most notably, both scans typically require you to lie on a table that slowly slides into a round, tunnel-like machine. They both create incredible images of the body, albeit in different ways. Imaging may be improving and becoming more detailed, but don’t forget how impressive the original X-ray was (and still is). Check out the history of the X-ray.