MRI (magnetic resonance imaging) uses powerful magnetic fields and radio waves — not radiation — to produce detailed images of organs, tissues and structures inside the body. It's an excellent diagnostic tool, but the experience itself can be daunting without preparation. Here's what to expect.
Before the scan
- Tell the scanning team about any metal implants — pacemakers, cochlear implants, surgical clips and some joint replacements may be incompatible with MRI
- Remove all jewellery, piercings and hair accessories before you arrive — the magnetic field will strip them
- Inform staff if you have tattoos (some older pigments contain metal and can heat slightly) or claustrophobia
- For abdominal scans, you may be asked to fast for 4–6 hours beforehand
- If a contrast agent (gadolinium) is being used, tell staff about kidney problems or previous contrast reactions
- Wear comfortable, loose clothing without metal zips or studs — or expect to change into a gown
During the scan
You'll lie on a table that slides into the scanner bore — a hollow tube roughly 60–70 cm in diameter and 1.5–2 m long. The scan produces a series of loud knocking and banging sounds from the gradient coils — you'll be given ear protection. Depending on the area being imaged, the scan takes between 20 and 90 minutes.
Stay as still as possible — movement blurs the images and may require sections to be repeated. If you're prone to claustrophobia, ask your doctor about mild sedation in advance. A squeeze ball is usually provided so you can signal the operator at any point.
After the scan
If no contrast was used, you can eat, drink and drive immediately. If gadolinium contrast was injected, drink plenty of water to help clear it — it's excreted through the kidneys. Results are usually available within 24–48 hours, though urgent cases may be read within hours.