What should you know about a large MRI scanner?

A large MRI scanner creates detailed images without x-rays, but safety screening and careful positioning are essential before the scan. The machine has a wide, tube-shaped opening, and the person lies on a table that moves through it while images are taken.

MRI uses a strong magnetic field and radio waves to produce images of soft tissues and selected body structures. The scanner is noisy, so ear protection is provided. The examination itself does not usually hurt, but staying still is necessary for clear images. Some scans use contrast material to make certain tissues easier to see. A large scanner may be chosen because the body area, equipment or positioning needs more space; the imaging team can explain which system is planned.

Tell the imaging team about pacemakers, implanted devices, metal fragments, aneurysm clips, medication pumps, pregnancy, kidney problems, allergies and previous difficulty in enclosed spaces. Remove metal objects and follow instructions about food, drink or medicines. Wear clothing without metal when advised. During the scan, you can communicate with the team and may be given an alarm button. If you feel anxious, discuss support before entering the scanner rather than stopping suddenly once imaging begins.

Tell the team immediately if you feel burning, unusual pain, breathing difficulty, severe distress or a sudden reaction after contrast material. Seek urgent help for serious breathing trouble, facial swelling or fainting after leaving the facility. If you cannot lie still because of pain or anxiety, contact the imaging service beforehand so an appropriate plan can be considered.

Ask what body area will be scanned, whether contrast is planned, how long you must remain still, and what to do about medicines or implants. Ask whether an open or wider scanner is available if enclosed spaces are difficult, and when and how the report will be shared.