Science
How does an MRI scan work?
An MRI scan works by using a powerful magnet and radio waves to make the water molecules in your body line up and send back signals. A computer turns those signals into detailed images of your organs and tissues — all without any X-ray radiation.
See it in motion.
Watch a 2-minute animated lesson that shows exactly how an MRI scan works.
Step by step
- 1A strong magnetic field aligns the body's water molecules.
- 2Radio waves nudge them, and they emit signals as they relax.
- 3Sensors detect these signals to map the body.
- 4It produces detailed images without ionizing radiation.
Frequently asked questions
- How does an MRI scan work?
- A strong magnet and radio waves make the body's water molecules emit signals that build a detailed image.
- Is an MRI safe?
- Generally yes — it uses no X-ray radiation, though strong magnets mean metal objects must be kept away.
- What's the difference between an MRI and an X-ray?
- X-rays use radiation to image bone; MRI uses magnets and radio waves to image soft tissues in detail.