MRI
MRI
At the London Imaging Centre, our state-of-the-art MRI scanner performs all well established work for most medical specialities (e.g. Orthopaedic, Neurology, Rheumatology, General Surgery etc) but also has some more specialist capabilities such as:
- Breast MRI
- Cardiac MRI
- Prostate Scanning
- Arthrography
- Tempero-mandibular joints
What is MRI?
Magnetic resonance imaging (MRI) is non-invasive medical imaging technique that uses radio frequency pulses and a strong magnetic field to obtain images from inside the body. MRI is non-invasive and involves no exposure to ionising radiation, however, you may be required to have a small injection of contrast medium in your arm to enhance the scan to show specific detail.
MRI for the detection, localisation, and assessment of disease or injury in most parts of the body. It is particularly helpful in assessing anatomical structures, organs and soft tissues for pathological conditions. In the brain, for example, it has a proven capacity to define some tumours and the plaques of Multiple Sclerosis which is provided by no other technique. In joints, it can pinpoint tears in muscles, ligaments of fluid with the joint. The need for biopsy or exploratory surgery may be eliminated in some cases, and can result in earlier diagnosis of many diseases or problems.
Magnetic resonance images differ from those produced by X-Rays. MRI images are based on proton density and relaxation dynamics within a magnetic field, which cause the tissues to emit a weak radio signal, not X-Rays passing through the body. These signals depend on the physical and chemical properties of the tissue and the timing parameters that the MRI Radiographer sets at the scanner controls.
The process of acquiring MRI images can be quite noisy, causing a knocking sound during the scan. We will give you ear phones for protection, through which you can listen to music during the scan - a pleasant way to pass the time, although you will need to remember to keep still throughout the scan (as with a photograph, if you move, the images will be blurred).
Generally, a scan takes 30 minutes. However, the exact duration will depend on which area of the body is being examined and whether more than one area is to be examined.
About your MRI appointment
Safety
Although there are no known side-effects associated with MRI, there are certain people who we cannot scan for safety reasons. They are people with pacemakers, metal fragments in their eyes, surgical clips or certain other types of implants. For this reason you will be asked to fill in a medical questionnaire and the radiographer will check your replies with you. We also try to avoid scanning patients during the early stages of pregnancy (1st trimester) unless there are good medical reasons for doing so. Please note that all underwear containing metal needs to be removed. Although we have private locking changing rooms on site, you may wish to wear loose baggy clothing with no metal e.g. tracksuit bottoms, t-shirt, sweatshirt etc to avoid changing into a gown and it would be helpful to remove metallic objects before scan appointment, which includes keys and body piercings where possible.
Before your appointment
There are a few MRI examinations that require preparation such as avoiding food and drink so it is important that you are clear about this prior to attending your appointment. Please check when making your appointment by phone, or read your appointment letter and information leaflet if sent out in the post.
If you, or the person having the scan need help because you speak a different language, please let us know when you book your appointment.
When you arrive
Your safety questionnaire will be checked; the radiographer will explain the procedure to you and will answer any questions you may have.
You will be asked to remove all metallic objects, credit cards, jewellery, spectacles and possibly, make-up. You may also be asked to change into a scanning and dressing gown.
The scan
Once you are ready for your scan, the radiographer will position you on the scanner couch and make you as comfortable as possible. It is vital that you lie still for the scan – being comfortable from the outset will help.
During the scan you will hear loud, rhythmic knocking sounds. This is normal. You will be given ear defenders to keep noise to a minimum and will be able to listen to music during your scan in most cases.
You will be given a buzzer to hold which you can use to summon attention and the radiographer can talk with you as the scan progresses.
In some parts of the body, the tissues may be lacking in natural contrast and a small injection may have to be given to enhance the images. In most instances, this injection will be given into a vein at the elbow. Please contact the London Imaging Centre if you have known renal (kidney) disease, a history of multiple or severe allergies or you would like to ask questions about the injection.
After the scan
Once the scan is finished you may go. The many images we have obtained will be studied by a Radiologist (a doctor expert in the interpretation of MRI scans) who will then send his report to the Consultant or doctor who originally referred you for the scan.
