They can examine various parts of the body and are used by the NHS on a daily basis.
What is an MRI scan?
An MRI scanner is a large tube that contains powerful magnets. Patients lie inside the tube during a scan.
An MRI scan can be used to examine almost any part of the body, including the:
-brain and spinal cord
-bones and joints
-heart and blood vessels
-internal organs, such as the liver, womb or prostate gland
The results of an MRI scan can be used to help diagnose conditions, plan treatments and assess how effective previous treatment has been, according to the NHS.
What happens during an MRI scan?
During an MRI scan, the patient lies flat on a bed which is then moved into the scanner.
Depending on which part of the body is being scanned, you'll be moved into the scanner either head first or feet first.
The MRI scanner is operated by a radiographer, who is trained in carrying out imaging investigations.
The radiographer controls the scanner using a computer, which is in a different room, in order to keep it away from the magnetic field generated by the scanner.
You will be able to talk to the radiographer through an intercom and they'll be able to see you on a television monitor throughout the scan.
At certain times during the scan, the scanner will make loud tapping noises, which are caused by the electric current in the scanner coils being turned on and off. During a scan, you will be given earplugs or headphones to wear.
It is very important to keep as still as possible while an MRI scan is taking place.
A scan can last 15 to 90 minutes, depending on the size of the area being scanned and how many images are being taken.
Who can have an MRI scan?
The NHS explains that an MRI is very safe and most people are able to have the procedure.
However, in some instances an MRI scan may not be recommended.
Before having an MRI scan, you should tell medical staff if:
-you think you have any metal in your body
-you are pregnant or breastfeeding
The strong magnets used during the scan can affect any metal implants or fragments in your body.
For more information about MRI scans visit the NHS website.