Magnetic Resonance Imaging (MRI)
Magnetic resonance imaging is a relatively new, although now widely established technology. The technique uses a magnetic field and radiofrequency pulses to stimulate all of the protons (mostly water) in your body, a faint radio wave then emmits from the protons as they recover from this stimulation. This radio wave is picked up by a large aerial inside the scanner and the information transformed by a powerful computer into images, which are the scan pictures we look at
Because of the powerful magnetic fields involved, when you have a scan it is very important to let us know if you have any metallic implants ( such as a pacemaker,heart valve, aneurysm clip or IUCD), or metallic foreign bodies ( such as metal in an eye from grinding etc
What is it Like?
The scan means lying very still in a tunnel on a moveable table. You will be given earplugs as the scanner is quite noisy. Even so you may still hear ticking, clanging and repetitive buzzing noises, these are entirely normal so don’t worry. The scans are very sensitive to movement so it is important that you stay very still. No X-rays are used at all, thus there is no limit to how many scans you can have
MRI scans provide doctors with very detailed images of virtually all parts of the body and are especially good at looking at the brain and spine, below is an example of an MRI image of the brain viewed from the side
An average scan of the spine takes about 15-20 minutes. For more complex scans of the brain, or when an injection of dye if given to highlight possible abnormalities this time can increase to 30 minutes. During the scan you will be able to talk to the radiographer perfoming the scan via an intercom.
What Happens If I Suffer With Claustrophobia?
Firstly, don’t worry. It is well known in MRI units that people suffer with claustrophobia and thus may have difficulty getting into the scanner. Modern scanners have a wider bore than older machines and thus you may find that having a scan is easier than you had thought. If necessary you can have a scan after taking some sedation. If you are claustrophobic, we generally recommend seeing your GP a couple of weeks before your scan to get some sedation, usually diazepam or a similar drug. You should take this 1-2 hours before your scan, and of course bring someone with you to take you home.
If you have severe claustrophobia, and have failed an attempt at an MRI scan with sedation, we will organise a scan on an open MRI scanner. This can result in a delay in getting your scan, and at the moment open MRI scanners produce images that are not quite as good as conventional MRI scanners
Arranging a Private MRI Scan
There is currently a huge demand for MRI scans on the NHS, thus waiting times for scans can be up to 3-4 months for ‘non-urgent’ conditions.
It is increasingly common for patients to request an MRI scan to be performed privately. This can be arranged if requested and avoids the 4-5 month wait. If you have no medical insurance and wish to pay for your own MRI scan I tend to send patients to the Cobalt Centre Magnetic Resonance Imaging Service Cheltenham (Tel 01242 535910), or the Princess Margaret Hospital in Windsor (Tel 01753743434)
The Cobalt Centre in Cheltenham website provides an excellent service and also has an open MRI scanner
The Manor Hospital In Oxford will also perform private MRI scans website
Getting Your Results
Rather than waiting for an outpatient appointment to get your results, I will do my best to contact each patient by telephone and let them know the results of their scan, and the treatment I recommend. Occasionally, I am unable to contact you and thus will send you a letter outlining the results of the scan and the treatment I recommend. Remember there is usually a delay in you having the scan and the scans / report reaching me, please be patient and I will give you your results as soon as I can. I will also inform your GP of any scan results and plan for treatment.
Some patients who are having follow-up scans as part of surveillance of a long-standing condition will be reviewed in outpatients with their scan results.