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.
MRI stands for magnetic resonance imaging. An MRI scan uses a combination of a strong magnet field and radio waves to produce detailed pictures of the inside of your body.
An MRI scan can help to diagnose your problem and help your doctor find the best treatment for you.
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, the brain and the joints. It is also helpful for looking at other parts of the body, often when other types of scan have not given a full picture. MRI scans do not use radiation.
MRI is a very safe procedure for most patients. Patients with heart pacemakers and certain other surgical implants, for example 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. This is done every time you attend for an MRI scan and is carried out on site before your scan begins.
National Safety Guidelines recommend that we do not scan pregnant women unless the scan is clinically urgent. The doctor who refers you for the scan, along with the radiologist (doctor who uses x-ray to diagnose and treat illnesses), will decide whether they believe your scan is necessary.
Many pregnant women have had MRI scans with no reported problems. If you have been referred for an MRI scan when you are pregnant please contact us prior to booking your scan.
If you cannot have a scan, for example if you have a pacemaker or suffer from claustrophobia, the radiologist may suggest an alternative type of imaging. This could be a CT scan or an ultrasound scan.
The radiographer (member of the radiology team trained to carry out scans) will ask you if you are happy for the scan to go ahead. This is called ‘verbal consent’ and may only involve the radiographer checking that you are booked for the correct scan. If you do not wish to have the scan or are undecided, please tell the radiographer.
It is your decision and you can change your mind at any time. Please bear in mind that not having the scan may delay your diagnosis as your doctors may not have all of the information that they need. Please remember that you can ask the radiographer any questions you have at any time before, during or after your scan.
In many cases you do not need to do anything to prepare for the scan. If you are taking any medication, please continue to take this. If we do need you to do anything in preparation, we will explain this to you when we confirm your appointment. There are some scans that need an injection of MRI dye. If this is the case we may ask you to fast for 4-6 hours.
If we are scanning certain areas of your body, we may need to give you 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 into a vein in your arm or your hand.
The contrast dye contains gadolinium, which may on rare occasions cause an allergic reaction. Please see our information leaflet about the injection also on our website.
Please wear clothes that are easy to remove as you maybe required to change into a hospital gown before you have your MRI scan. This is because some fabrics contain metallic fibres that may heat up during the scan.
Lockers are provided for your clothes and valuables. Anything metallic, such as coins, watches or mobile phones, may be magnetic and be pulled into the scanner. Similarly, cards with a magnetic strip along the back, such as credit or oyster cards, will have the data on them deleted and will stop working.
If we are scanning your head, you will need to remove any dentures that contain metal. The scan will not affect dental fillings. Hairclips and wigs must also be removed if they contain metal. Lockers are provided to store your clothes and valuables during your scan.
Before the scan takes place, you will be given the opportunity to ask the radiographer any questions you have.
We will ask you to lie on the scanner bed where we will make you as comfortable as possible. If you are not comfortable, please tell us as you will need to keep very still during the scan. It is important that you do not move, or the pictures could be blurred and the scan will have to be repeated.
Once you are comfortable and positioned correctly, we will slide the scanner bed with you on it into the scanner – the part of your body that we are scanning 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.
When the scanner is working, it makes a loud banging noise. We will give you headphones to wear to reduce the noise. There are also ear plugs and eye masks available on request. You can listen to music while you are being scanned. You will also be given a buzzer to squeeze if you need to attract our attention during your scan.
This depends on which part of your body is being scanned and the information that your doctor needs. You will be given enough time for your specific scan when your appointment is made and the radiographer will tell you how long he/she expects your scan more specifically to take when positioning you.
The scan should be completely painless. Make sure you are as comfortable as possible before we start and try to relax. The scanner is a short tunnel so please let us know before you come for your scan if you suffer majorly with claustrophobia.
The radiographer will talk to you during the scan to let you know what is happening. If you are particularly anxious, a friend or relative can stay in the room with you during the scan, however many people find the radiographer enough support.
Unfortunately we are not able to offer childcare facilities and your children cannot go into the scan room with you. If you need to bring your children with you, please bring along an adult who can look after them while you are having the examination.
As soon as the scan is finished you can go home. You can eat and drink as normal and resume your usual activities.
The pictures taken during the scan are carefully studied by the radiologist who will produce a detailed report.
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 the MRI department where you had your scan for advice. If it is urgent or out of hours, contact your local emergency department (A&E).
The results will be sent to the doctor who referred you for the scan. Our reporting turnaround time is 5 working days however 90% of the time the report reaches the consultant within 24hrs.
For advice, support or to raise a concern, contact your consultant or the imaging department. To make a complaint, contact the complaints department.