An MRI scan, also known simply as an MRI, is way of scanning the body using magnetic fields and radio frequency. MRI stands for Magnetic Resonance Imaging.
It can capture lots of soft tissue definition which other imaging modalities can't show you. It can also look at vascular systems and some bone.
The most common conditions to necessitate an MRI scan include injuries in the knee, spine, ankle and all major joints. The conditions could stem from sports injuries, trauma and degenerative changes.
We also commonly image the liver and gallbladder, helping to check for liver disease and gallstones respectively. Other common scans include the bowel and female pelvis, checking for conditions such as lesions and tumours.
An MRI can examine all parts of the body except for the lungs. Basically, any part in the body that has water in it can be imaged. Since the lungs don’t have water in them, they can't be imaged. But the healthcare sector is researching new ways to eventually scan the lungs.
To arrange get an MRI, a you need a referral from your clinician. The department will contact you to arrange the scan.
Private and self-pay patients typically are offered a scan appointment within 2-working days. The hospital usually reports the results back to the clinician within 24 to 48 hours after the scan. It is then up to you to get your results in a follow-up appointment with your clinician.
Because of the pulling effect of the magnet, you can’t have an MRI scan if you have certain aneurism clips, a pacemaker or metal fragments in your eyes. Nor should you have an MRI scan if you had surgery in the six weeks prior. We would advise women in their first trimester of pregnancy to not have an MRI scan.
The medical team will make sure you fulfil the requirements to have an MRI scan before your appointment.
We would advise women in their first trimester of pregnancy to not have an MRI scan.
You just lie down on the MRI couch. Then, the couch and you are fed into the bore of a large magnet. The magnetism is always on. The magnet is in the shape of a long cylinder, so when you go into that, you are in a magnetic field.
Sometimes, before the scan, you will drink, or will be injected with, a contrast liquid. The liquid highlights more details of specific parts of the body in the scan results. After the scan, you are advised to drink fluids to flush out the contrast liquid from your body if it has been administered.
The machine uses technology called ‘gradients’ to scan the body at different angles, which highlights certain parts within the body. The machine uses 3 gradients of magnetic fields: an X axis gradient, a Y axis gradient and a Z axis gradient. Each gradient makes a different knocking noise during scanning.
The machines at Circle are all 1.5 Tesla, a unit of a magnet’s strength.
It usually takes anywhere between 15 minutes to one hour and a quarter, depending on the body parts scanned. For example, a scan of the knee could take about 25 minutes. Whereas a scan of the entire spine could take around 1-hour.
No, an MRI does not hurt.
You might feel uncomfortable from the machine’s noise. So we give you earplugs or ear defenders, through which we can pipe music if you wish.
You might also feel uncomfortable in the bore of the magnet because it is a small space, especially if you are claustrophobic. The radiographer supports you by talking through the situation with you before and during the scan – explaining how the technology works and discussing any anxieties. The radiographer sits opposite a large window, so he or she can see you throughout the scan. You have an alarm you can buzz at any time, which signals the radiographer to remove you from the machine.
There are no known side effects of an MRI’s magnetic field. There is a small number of people who can adversely react to the contrast liquid.