What is Magnetic Resonance Imaging (MRI)?
This procedure provides detailed images of soft tissue, bone, fat, muscles and the internal organs of your body. A series of images are taken through sections of your body, in any direction desired. MRI produces different information from other examinations such as x-ray, ultrasound or CT Scans. In particular, it provides information concerning the soft tissues including nerves, muscles, ligaments and cartilage.
The MRI machine uses a very strong magnetic field and radiowaves to examine a specific area of your body. This technique does not use x-rays and is considered safe and painless.
The examination is performed by an MRI technologist (a technologist trained in medical imaging who has studied further in MRI) and interpreted by a Radiologist (a doctor who specialises in medical imaging).
Preparing for your MRI?
In general, MRI does not require specific preparation. It is often performed in conjunction with CT scans or plain x-rays. Please bring any previous films with you to your appointment. Please advise your doctor, the receptionist as well as the technologist when you arrive if you have a pacemaker, cerebral aneurysm clips or a surgically implanted medical device. People with cardiac pacemakers and cochlear implants cannot be examined by MRI.
Please tell the receptionist if there is a possibility that you are pregnant. You should also inform staff if you have had a piece of metal in your eye or brain or if you have had eye surgery.
What happens during the MRI scan?
You may be asked to change into a gown as shadows from your clothing will interfere with the imaging process. The equipment has a strong magnetic field, and you will also be asked to leave jewellery, keys and credit cards outside the examination room. Lockers are available for your belongings.
The MRI technologist will position you on the table of the scanner. You will need to remain as still as possible. Throughout the procedure you will be able to hear and talk to the technologist who will be monitoring the examination from an adjacent room.
The magnet makes a knocking and humming sound when scanning. In some circumstances you can listen to music with headphones if you wish, so the noise is less disturbing. When the knocking stops, the computer processes the images for a few seconds before the next scan. It is important not to move or change position.
In some cases it may be necessary to show the blood vessels in your body, and intravenous (via the vein) administration of a special fluid, known as a contrast will be required. Sometimes, a slight sense of warmth or flush may occur and as with all intravenous injections, there is a small chance of an allergic reaction. Although this is rare, a reaction can be very serious. Therefore it is important to tell the staff if you have had any form of reaction to x-ray contrast before, or if you are an asthmatic.
Please inform the receptionist if you suffer from severe claustrophobia as you may need sedation for this test.