MRI – magnetic resonance imaging
What – an MRI scanner uses magnetic fields and radio pulses to look in detail at tissues. It does not involve exposing you to any ionizing radiation and does not damage body tissues. MRI is painless but you may need a needle in your hand for delivery of a contrast agent to enhance the images.
Why – an MRI scan may be requested for many reasons but is usually performed to assess and look for structural abnormalities or variations inside the tissues of your body.
Preparation – no specific preparation for the MRI is required but you will be required to remove / take off any metal objects that you normally would wear – watches, jewelry etc… You will be asked a series of questions to make sure that you have not forgotten anything before you enter the scanner – some pacemakers are MRI compliant and this will need to be checked beforehand. The scan itself will involve lying on a table and the relevant part of your body entering into a strong magnetic field (a big metal doughnut). In order to concentrate the magnetic field the hole in the doughnut is small and therefore the fit can be tight. The scan takes usually 15-30 minutes to perform depending upon the number of image sequences required and during each sequence the machine will make a lot of noise – like a building site! You may be provided with headphones but you will be required to keep very still throughout in order to get the best images.
Risk – the procedure is painless and the MRI itself is risk free. There is however, always a very small risk that someone could react seriously to any injection and this includes the contrast agent that may be required. The risk is however very small. Some people who are claustrophobic find the experience a little unpleasant and some may find it a little tedious.
How long will it take – an MRI scan takes usually 15-30 minutes to perform depending upon the number of image sequences required. Remember to turn up in good time and that there could also be a queue!