MRI scan

This patient information aims to answer some of the questions you may have about having an MRI scan. It explains the benefits, risks and alternatives to the procedure.  It explains what you can expect when you come to hospital. If you have any further questions please speak to your consultant or the imaging department.

Download the print handout version

What is an MRI scan?

MRI (magnetic resonance imaging) scans use a combination of a strong magnet field and radio waves to produce detailed pictures of the inside of your body.

What are the benefits of an MRI scan?

An MRI scan provides much more detailed pictures of your body than an ordinary X-ray. It is particularly good at identifying problems in the spine, brain and joints, but also helpful for looking at other parts of the body.

MRI scans do not use radiation.

Are there any risks?

MRI is a very safe procedure for most patients. Patients with heart pacemakers and certain other surgical implants (e.g. cochlear implants) may not be able to be scanned. You will be asked to complete and sign a safety questionnaire before your scan to make sure it is safe for you to be scanned.

Is it safe to be scanned if pregnant?

National Safety Guidelines recommend that we do not scan those who are pregnant unless the scan is clinically urgent. Your doctor will decide. If you have been referred for an MRI scan and are pregnant please contact us prior to booking.

Are there any alternatives?

If you cannot have a scan (e.g. if you have a pacemaker or suffer from claustrophobia) the radiologist may suggest an alternative type of imaging.

Asking for your consent

The radiologist will ask if you are happy for the scan to go ahead (verbal consent). You will also be asked to sign a form which states that you agree to have the injection and understand what it involves. If you do not wish to have the scan or are undecided, please tell the radiographer/radiologist. Please ask any questions you have at any time before, during or after your scan.

How to prepare for the scan

If we need you to do anything to prepare, we will explain this when we confirm your appointment. If you are taking any medication, please continue to do so. If you have any devices in or attached to your body, or if you are a diabetic, please contact the Imaging department before your scan.

Will I need an injection?

You may need an injection of contrast (dye.) The dye shows up on the scan and gives us more detailed pictures, particularly of your blood vessels. The injection will be given to you by inserting a small needle in your arm or hand.

Please refer to our leaflet about injections.

What do I need to wear?

You will need to change into a gown prior to your scan and remove anything metallic or electronic. Lockers are provided for your clothes and valuables. If we are scanning your head, you will need to remove any dentures that contain metal. Hairclips and wigs containing metal must also be removed.

What happens during the scan?

We will explain the scan and ask you to lie on the scanner bed where we will make you comfortable. This is important as the scan will be longer if there is movement. We will slide you into the scanner – the part of your body being scanned must be in the centre of the machine. For scans of the chest or abdomen, you may be asked to hold your breath for a short while. You will be provided with earplugs and headphones and music to be played at your choice. This will protect your hearing and soften the sound of the scanner. You can press a buzzer if you need to stop the scan.

How long will the scan take?

This depends on which part your body is being scanned, the information your doctor needs and any movement during the scan.

Will there be anyone with me?

The radiographer will talk to you during the scan to let you know what is happening. Please let us know if you have any concerns.

Can I bring my children?

We do not have childcare facilities and children cannot go into the scan room with you.

If you need to bring your children with you, please bring an adult who can look after them while you are having the examination, without a supervising adult your scan will need to be rebooked

What happens afterwards?

You can return to normal activities and eat and drink as normal. If you had the injection of contrast dye, an allergic reaction can very rarely occur up to two days after the scan (please read the injection information). If this happens, please contact our Imaging department for advice. If it is urgent or out of hours, contact A&E.

When will I get the results?

The results will be sent to your referring doctor within 48hrs.

Contact us

Please contact the Imaging team about any general concerns on 0207 467 4317. However, if you experience any symptoms of concern please contact your GP or go to your local Emergency Department (A&E).

Your comments and concerns

If you have any questions or concerns about your medicines, please speak to the staff caring for you. For support or advice please speak to your consultant or the Imaging department on 0207 467 4317.

Language and accessible support services

If you need an interpreter or information about your care in a different language or format, please get in touch.

Would you like to know more about the MRI Scanner and MRI Safety?

Watch this 5 minute safety video from Siemens Healthcare