What is an MRI?

What actually happens during an MRI, and how should I prepare?

An MRI (magnetic resonance imaging) scan uses a strong magnetic field and radio waves to create detailed images of the inside of the body. There is no ionizing radiation involved.

You lie on a table that slides into a tube-shaped scanner. The machine is loud, so ear protection is provided. Most scans take 20–60 minutes, and staying still is the main thing asked of you.

Key points

Tell the team about any implanted metal, devices, or possible pregnancy before the scan.
Some scans use a contrast agent given through an IV — ask why if it applies to you.
If enclosed spaces are difficult for you, say so in advance; there are options.

Questions to ask

Why is an MRI being ordered instead of another test?
Will contrast be used?
Who explains the results to me, and when?

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Sources & transparency

MRI Scans(opens in a new tab)
MedlinePlus (U.S. National Library of Medicine)
Retrieved by Phoenix Jul 10, 2026

Last reviewed:: Jul 15, 2026
Next review due:: Jan 15, 2027
Editorial owner:: Phoenix Health Compass Editorial Team
Medical reviewer:: Not yet clinically reviewed