MRI scan

An MRI scan uses magnetism to build up a detailed picture of the inside of your body.

What is an MRI scan?

An MRI scan uses magnetism to build up a picture of the inside of your body. MRI stands for magnetic resonance imaging.

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Why might I need an MRI?

Doctors might use an MRI scan to show:

  • if a lump or abnormal area is cancer or not
  • the size of the cancer and if it has spread.

What happens during an MRI?

Before the scan

The hospital will send you information about the scan so you know what to expect. If you are having a scan of your tummy (abdomen), you might be asked to not eat anything for a few hours before the scan. This helps to get a clear picture.

Some people feel a bit claustrophobic in the scanner. If you are worried about the scan, you may be able to have a sedative to help you relax while you are being scanned. You should ask your GP or doctor about a sedative before you go for the scan.

On the day of the scan, the radiographer will tell you what you need to do. You can ask them any questions you have. You can also tell them if it is difficult for you to lie still, or if you get anxious about being in small spaces. They will give you lots of support.

The scanner is a powerful magnet so you will be asked to complete and sign a checklist to make sure it is safe for you. The checklist asks about any metal implants you have, such as surgical clips, bone pins, artificial joints and heart valves. It also asks about electrical devices, such as a pacemaker, implanted defibrillators, nerve stimulators or cochlear implants. You should also tell your doctor, or the radiographer who does the scan, if you have ever worked with metal or in the metal industry. As very tiny fragments of metal can sometimes lodge in the body, especially in the eyes.

Having metal in your body does not necessarily mean you cannot have an MRI scan. Your doctor and radiographer will decide if the MRI scan is safe for you. If you are not able to have an MRI scan, another type of scan can be used.

You should tell the radiographer if you are pregnant or think you could be.

You can usually wear your own clothes if they do not have metal zips or buttons. Don’t worry if you do not have clothes without metal, you can change into a gown.

During the scan

You will be asked to lie very still on a bed inside a cylinder (tube). The bed moves slowly through the middle of the scanner.

A person lying in an MRI scanner being positioned by a radiographer

The radiographer leaves the room during the scan, but can see you through a screen. You will be able to talk to them through an intercom while you are having the scan.

The scan is not painful, but lying still on the bed during the scan can be a bit uncomfortable. It usually takes between 15 minutes and an hour. The scanner is very noisy and you will be given earplugs or headphones. It may be possible to listen to music during the scan.

You will need to lie still on the bed as any movement can affect your results. If you get uncomfortable, let the radiographer know. Some people find it helpful to close their eyes while they are in the tunnel.

Some people are given an injection of a dye into a vein in the arm during the scan. It does not usually cause any discomfort. The dye is called a contrast medium. It helps certain types of tissues to show up more clearly on the scan. It is only given when necessary. The radiographer or doctor will tell you more about the contrast if you need to have it.

Some tattoos contain metal, especially those with red dye in them. These can cause a warm, or sometimes burning feeling during the scan. This is only in the area of skin where the tattoo is. If this happens, let the radiographer know straight away.

After the scan

You can usually go home straight after the scan. If you have had a sedative, you should not drive for 24 hours. Ask a family member or friend to drive you home.

You will usually get the results within a couple of weeks. Waiting for test results can be a worrying time. Talking to your family and friends about how you feel can help. You can also speak to your doctor or nurse if you have any problems, or need more support.