MRI uses a powerful magnetic field and radio waves to create detailed images without ionising radiation. It is widely used, but safety screening is essential because the magnetic field can interact with some implants, devices and metal objects. Completing the safety questionnaire accurately helps the team decide whether and how the examination can be performed.
Tell us about implants, medical devices, previous surgery or possible metal fragments before booking. Our team will help coordinate the required MRI safety checks with the imaging provider. Appointments can usually be arranged within 1–3 days, with results provided within 3 days of your scan.
Why does MRI require special safety checks?
The scanner’s magnet is powerful and remains active. Some metal objects can move or heat up, and some electronic implants may not be compatible with the scanner or scanning conditions. Metal can also distort images. The team must assess risks before you enter the MRI room.
Having an implant does not automatically mean MRI is impossible. Some devices are MRI-safe or MRI-conditional under specific requirements, but the exact make, model and circumstances may need to be verified. Never assume a device is compatible without checking.
What should you tell the imaging team?
Tell the provider if you have or have ever had a pacemaker, defibrillator, cochlear implant, neurostimulator, insulin pump, aneurysm clip, artificial valve, surgical clips, metal plates or other implanted device. Also mention metal fragments, particularly in the eyes, and previous injuries involving metal.
Tell the team about previous surgery, pregnancy or possible pregnancy, kidney problems, previous contrast reactions and severe claustrophobia. Complete every question honestly, even if you think a detail is old or unimportant.
What happens before entering the scanner room?
You may be asked to remove jewellery, watches, piercings, hearing aids, coins, keys, cards and clothing containing metal. Depending on the examination, you may change into a gown. The team will explain any additional checks needed for your implant or medical history.
Do not bring oxygen cylinders, mobility equipment or other items into the scan room unless the MRI team has confirmed they are safe for use there. Staff will guide you through the process.
Is MRI safe during pregnancy?
Tell the provider if you are pregnant or might be pregnant. MRI may be used during pregnancy when clinically justified, but the decision depends on the circumstances and the examination. Contrast is considered separately and is not routinely used during pregnancy unless there is a clear clinical reason.
Do not cancel a medically important scan without discussing it with your doctor arranging it. The team can explain the expected benefit, any uncertainties and whether another examination is suitable.
What about noise, heating and claustrophobia?
MRI scanners make loud knocking and buzzing sounds, so earplugs or headphones are provided. You need to stay still, and some people feel enclosed. Tell the team beforehand if you have severe anxiety or difficulty lying still.
You may feel slight warmth during the scan, but report any discomfort, burning sensation or concern to the radiographer immediately. You will be able to communicate with the team during the examination.
Can everyone have an MRI?
Suitability depends on the scan, device, medical history and local safety procedures. If the team cannot confirm that a device is safe under the proposed conditions, the scan may need to be delayed while more information is obtained or another test considered.
Bring implant identification cards and any relevant device details if you have them. Giving accurate information early can reduce delays and help the team plan an appropriate examination.
Why MRI safety screening is essential
MRI scanners use a powerful magnetic field. Certain metal objects can move, heat up or interfere with image quality, and some implanted electronic devices can be affected unless specific conditions are followed. Before scanning, the team will ask about surgery, implanted devices, metal fragments, shrapnel injuries, hearing implants, pacemakers, neurostimulators, insulin pumps and other relevant equipment.
Do not assume that an implant automatically prevents MRI, or that it is safe because it has been in place for years. Some devices are labelled MR Conditional and can be scanned only under defined conditions. The imaging team may need the exact make and model, an implant card or confirmation from the specialist team before deciding whether and how to proceed.
Contrast, kidney disease and pregnancy
Tell the team about kidney disease, dialysis, pregnancy or possible pregnancy, allergies and any previous reaction to MRI contrast. Contrast is not required for every MRI, and the decision to use it depends on the clinical question. Where it is needed, the team will assess relevant risks and explain the procedure.
If you are pregnant or think you may be, tell your doctor before the scan so the benefits, timing and alternatives can be considered. MRI does not use ionising radiation, but this does not remove the need for safety screening or clinical justification. Follow the instructions provided for your particular examination.
What if you are unsure about an implant?
Contact the imaging provider before attending if you do not know the details of an implant or have been told that a device may be incompatible with MRI. Provide any implant card, operation letter or contact details for the team that fitted it. If the device cannot be verified in time, the appointment may need to be delayed while the safety conditions are checked.
Never conceal an implant or metal injury because you are worried about losing an appointment. Accurate information helps staff choose the safest approach and avoid an examination that cannot be completed. If MRI is not appropriate, the referring doctor can consider whether another imaging test would answer the clinical question.
Sources and further reading
These NHS resources provide further information. They do not replace individual clinical advice.
This article is for general information only and does not replace an individual assessment or advice from a qualified healthcare professional. Scan suitability and preparation depend on your circumstances and the specific examination. If you are worried about symptoms, speak to a healthcare professional. Seek urgent help for emergency symptoms.
Frequently asked questions
Answers to common questions about your scan, how to prepare and what happens next.
Can I have an MRI with a pacemaker?
Some devices may be scanned under specific conditions, while others may not be suitable. The team must identify the exact device and follow the relevant safety protocol.
Can metal fillings or joint replacements stop me having an MRI?
Many common dental fillings and some orthopaedic implants are compatible, but the team needs accurate details. Never assume an implant is safe without screening.
Does MRI use radiation?
MRI does not use ionising radiation. It uses a strong magnetic field and radio waves, which is why specific safety screening is essential.
What if I have a metal fragment in my eye?
Tell the imaging team before the appointment, especially if you have worked with metal or had an eye injury. They will decide what checks are needed before scanning.
Ready to arrange your scan?
At PrivateScans, we make arranging your scan straightforward. Appointments can usually be arranged within 1–3 days, and your results are provided within 3 days of your scan. When you’re ready, book online. If you have questions before booking, our team is here to help.