What is the difference between them?
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X-ray shines light (x-rays, our eyes can’t see them), and the picture is the shadow. The x-ray picture is a photo negative, so the shadows are white and the bits where light shines through are dark. The denser stuff that blocks light, like bones, are white.
A CT (computed tomography) scan is x-rays again, but you take lots of pictures from different angles and use a computer to stitch them together into a 2-D view so you get an x-ray that looks like you sawed a person in half and are peering down on the slice. This is useful to get a detailed view to look at the size and shape of things.
MRI (magnetic resonance imaging) is completely different. It uses a giant magnet and radio waves to cause certain atoms to spin, and then uses a ring of antennas to detect when they pop back (they “squeak” a little radio signal). A computer then creates an image from the radio signals kind of like the CT scan computer does. MRI shows much greater detail for softer tissue- the sort of stuff x-rays mostly pass through), and can show sharper images than CT scans. It’s great for looking at squishy things like brains.
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