MRI (Magnetic Resonance Imaging)

MRI equipment

About your MRI Scan

What is MRI?

Magnetic Resonance Imaging (MRI) is a scanning technique which uses a magnetic field, radio waves and a powerful computer to produce highly detailed images of the inside of the body.

What are the benefits of an MRI scan?

It is incredibly sensitive for imaging soft tissue structures including the brain, spinal cord, joints and internal organs, without causing discomfort. It provides doctors with more information than some other tests.

Are there any risks?

MRI is very safe. MRI does not use X-rays or any ionising radiation and does not have any known side effects.

Because of the strong magnetic field associated with MRI scanning it is very important to remove metallic objects and to screen patients for devices such as pacemakers and metallic implants which are affected by the field.

Before the scan

If you need any special preparation for your scan a separate instruction sheet will be provided with this leaflet and your appointment details.

Where is MRI?

When you come to the hospital for your scan, please take the escalator to the 1st Floor and make your way to the Imaging Department at the back of the building. Please report to the main X-ray Reception where you will be directed to the MRI Department.

When you arrive

Important note: You must arrive before your appointment time. Your letter will have information on your arrival time. If you do not arrive in good time, your scan may need to be rescheduled.

A member of the MRI staff will greet you to explain the scan procedure and answer any questions you may have. You will be taken through a safety check and asked to remove any loose metal objects including watches, coins and any credit cards. These will be locked away while you have your scan.

MRI is not affected by clothing but metal zips and buttons can affect the images and you will be asked to change into a gown.

How long will my scan last?

Most scans last between 15 and 40 minutes depending on the type of examination you are having. You should allow for extra time in the unit because emergency cases sometimes have to be fitted in at short notice.

Can I bring someone with me?

If you suffer from claustrophobia or are apprehensive about your scan you may bring a friend or relative with you. They may accompany you into the scanning room providing that they too meet the safety regulations.

What happens during the scan?

The radiographer will make you comfortable on the scanning couch and then will move you into the scanner. You will be able to talk and hear the radiographer throughout the scan, via a two-way intercom. You will also be given a patient alarm should you wish to call the radiographer during the examination.

During the scan you will hear a loud, rhythmic drumming noise which periodically stops and starts. This is the normal operation of the scanner and is nothing to worry about.

Because the noise made by the scanner is quite loud we can play a music CD for you through headphones or provide you with earplugs to make you more comfortable.

From the time that you are moved into the scanner to the end of the examination it is important that you keep absolutely still to avoid blurring the images.

Some patients may require an injection of a dye/contrast agent or muscle relaxant during the scan. The injections are given to improve the picture quality and/or to give the doctors more information about certain parts of the body. As with any injection there may be a very small risk of a reaction. Your radiographer will discuss this with you.

Breastfeeding mothers should be aware that the contrast agent can cause breast milk to taste slightly bitter, and so they are advised not to breastfeed for 24 hours after their injection.

What happens after the scan?

The images produced during the scan will be reviewed by a consultant radiologist who will produce a report. This report will be sent to the doctor who referred you and discussed at your next clinic appointment.

You should arrange your clinic appointment for two weeks after your scan date to get your results. The images produced during the scan will be reviewed by a consultant radiologist who will produce a report. This report will be sent to the doctor who referred you and discussed at your next clinic appointment.

You should arrange your clinic appointment for two weeks after your scan date to get your results. 

Are you suitable?

Not everyone is suitable for an MRI scan and it is important that you let us know if you:

  • Have a cardiac pacemaker
  • Have a cerebral artery aneurysm clip
  • Have had recent surgery
  • Have any metallic implants in your body
  • Have a history of working with metal, or if you have ever had a metallic foreign body in your eye
  • Are very claustrophobic
  • Weigh more than 200 kg
  • Are or think you may be pregnant
  • Are breastfeeding

Please note: Any body piercings must be removed before your scan.

Contact Information 

If you think you may be unsuitable please call 020 3315 2055 and speak to a radiographer. 

Imaging Department
1st Floor, Lift Bank D
Chelsea and Westminster Hospital
369 Fulham Road
London
SW10 9NH

Mon–Fri, 9am–5pm

If you need to change your appointment date or if you require an interpreter for your examination please call 020 3315 2195.

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