MRI stands for Magnetic Resonance Imaging. This type of scan is quite common. It produces detailed pictures of the body. Instead of X-rays it uses a large magnet and radio frequency waves that are fed into a computer. The computer then builds up cross-sectional images of your body. If you need an MRI scan, more written information will be available from your local scanning department. There are only a certain number of appointments for MRI scans, so it is very important that you do not miss your appointment. Also, please remember that you will not be able to have a scan unless you have an appointment.
There is no special preparation needed for an MRI scan. However, because of the powerful magnet used to produce the scans, safety guidelines must be followed. You will have to fill in a questionnaire and return it by post before the scan can be carried out.
It may not be possible to have a MRI scan if you have:
- a heart pacemaker;
- some types of surgical clips inside your head;
- metal fragments in your eyes or elsewhere; or
- neuron-stimulator implants.
Please tell your doctor or nurse if you:
- have any allergies;
- have asthma;
- have diabetes;
- have kidney problems;
- are taking any medication;
- are pregnant;
- have had any surgery in the past 12 weeks;
- are in any doubt about your suitability for an MRI scan; or
- have had any problems before with any type of X-ray or radiology examination.
What will happen? For the scan:
- wear something loose without metal zips or buttons;
- remove all metal objects, including rings, before scanning – remember to check your pockets;
- make sure you do not have credit cards in your pockets, etc. – the magnetic strip is affected by the scan; and
- leave valuables at home. (The staff can lock them away, but it is better if you don’t bring anything valuable to the hospital.)
If necessary, you will have an injection of dye into a vein in your arm. This can help improve the images. You will be asked to lie on a scan table in a type of tunnel. The table contains the magnet and the part of your body to be scanned lies directly over its centre. The table moves into position inside the tunnel and although you will not feel anything, there will be quite a lot of noise. All you need to do is try and relax and keep still while the pictures are being taken.
Because of the noise, you will be given earplugs, and headphones may be available. Then you can listen to a CD or an audiotape. An MRI scan usually takes about 20 to 30 minutes. Sometimes, however, it can take up to an hour, and sometimes it is much shorter. The radiographer stays outside the room, but you can communicate with him/her through a microphone. The radiographers are very experienced and will do all they can to help you to relax.
You may be able to bring a relative or friend with you when you come to the clinic. They can stay in the waiting room while you have your scan. Please check with the radiology department first, in case the clinic is very busy.
When will I get the results?
At the end of the scan there could be up to 100 images for the radiologist to look at. Once these have been carefully studied, a report will be sent to your consultant. Please make sure you have an appointment to get the results.