MRI stands for Magnetic Resonance Imaging. A combination of a strong magnet and radio waves are interpreted by a computer to produce highly detailed pictures of the inside of your body. Unlike X-rays and CT scans, MRI scans do not use radiation. An MRI scan can help us find the cause of your problem and the best treatment options for you and has no known side effects. MRI scans are particularly good at identifying problems in the spine, brain and joints, but have also been used in a wide variety of other ailments in different parts of the body. A standard X-ray does not give the same level of detail as an MRI scan.
Sometimes we need to give you an injection of contrast dye before the scan. This is a dye which makes the blood vessels and organs show up more clearly. This will be given by a qualified member of staff, usually in the arm. This dye contains a substance called gadolinium. We may need to check your kidney function since the dye is eliminated from the body through the kidneys; we do this by sending you for a blood test before your appointment.
Risks
An MRI is a very safe procedure, but because it uses a very powerful magnet, some people cannot enter the MR controlled area and then have an MRI scan. Although there are no known side effects associated with MRI, there are certain people who we may not be able to scan for safety reasons. They are people with pacemakers, a history of metal fragments in their eyes, surgical clips and other types of implant. For this reason patients are asked to fill in a medical safety questionnaire; it is essential you answer these honestly as there is no way to stop the magnet affecting people once they enter the MR scanner. If you cannot have an MRI scan, there are alternatives such as CT and ultrasound scans.
You can eat and drink normally and take your usual medications before your scan unless you have been instructed not to by the MRI department.
What to expect
When you arrive, a member of staff will check your details and go over the safety questions with you to ensure that you are safe to enter the scanner area. A radiographer will explain the procedure to you and will answer any questions you may have. You will be asked to remove all loose metal objects such as watches, jewellery and credit cards and asked to change into a hospital gown. There are lockers in the department so that your belongings can be securely locked away and the key will accompany you into the scanner.
You will then be taken into the scan room and the Radiographer will ask you to lie on the scanner bed and position you correctly and as comfortably as possible. During the scan you will hear loud, rhythmic knocking sounds. This is normal and you will be given ear plugs and ear defenders to keep the noise to a minimum. It is also possible to have the radio on during the scan so you can listen to some music. Once you are set up within the scanner, the Radiographer will go into the adjoining room (where the control equipment is located) to speak to you through the headphones. There is a large window, and the Radiographers can see you throughout the whole examination. Also, you will be given an alarm bell to hold and then squeeze if necessary which gives a signal to the Radiographer that you have a problem.
You will need to keep very still during the scan to avoid blurring the images. Sometimes there are periods of time where the scanner is quiet, but we ask you to try to keep still during these times as well. The scan is completely painless and will usually take between 20 and 60 minutes. You may feel a slight vibration and apart from that and the noise you will not be aware that anything is happening. It is not usually necessary to have someone come with you into the scan room, but if you feel particularly nervous it might be possible for a friend or relative to accompany you, provided it is safe for them to do so.
Afterwards
Once the scan is finished you may go. The many images we have obtained will be studied by a Radiologist (a doctor, who is an expert in the interpretation of X-rays and MRI scans), who will send their report to the doctor or health care professional who requested the scan for you. You will not get the results of your examination on the same day.
Please do not ask the Radiographer what your scan has shown. Although they are highly skilled professionals, it is not the Radiographer’s job to make a diagnosis.
There are no after effects from your scan, you can carry on with your normal activities including driving and going back to work.
