MRI scan 

Introduction 

MRI scans use strong magnetic fields to produce detailed images of the inside of the body 

Health checks: later years

Once you reach the age of 65, your regular NHS health checks will include some new ones

Magnetic resonance imaging (MRI) is a type of scan used to diagnose health conditions that affect organs, tissue and bone.

MRI scanners use strong magnetic fields and radio waves to produce detailed images of the inside of the body.

An MRI scanner is a large tube that contains a series of powerful magnets. You lie inside the tube during the scan.

An MRI scan can be used to investigate almost any part of the body including the:

  • brain and spinal cord
  • bones and joints
  • breasts
  • heart and blood vessels
  • internal organs, such as the lungs and liver

Read more about why MRI scans are used.

What happens during an MRI scan?

During an MRI scan, you lie on a flat bed which is moved into the scanning tube. Depending on the part of your body being scanned, you will be moved into the scanner either head first or feet first.

The MRI scanner is controlled by a computer which is in a different room from the scanner. This is to keep it away from the magnetic field generated by the scanner. 

A radiographer will operate the computer. A radiographer is someone who is trained in carrying out X-rays and similar procedures. You will be able to talk to them through an intercom and they will be able to see you on a television monitor throughout the scan.

At certain times during the MRI scan, the scanner will make a loud clicking sound. This is the magnets being turned on and off. You will be given earplugs or headphones to wear.

It is very important that you keep still during your MRI scan. The scan will last between 15 and 90 minutes, depending on the size of the area being scanned and how many images are taken.

Read more about how an MRI scan is performed.

Safety

An MRI scan is a painless and harmless procedure. You may experience a slight sense of claustrophobia (fear of enclosed spaces) when you are inside the scanner.

Unlike X-rays, MRI scans do not involve exposing the body to radiation. This means that people who may be vulnerable to the effects of radiation, such as pregnant women and babies, can safely use them.

However, not everyone can have an MRI scan. For example, they are not recommended for people who have certain types of implants fitted, such as a pacemaker (a battery operated device that helps control an irregular heartbeat).

Read more about when MRI scans are not recommended.

Extensive research has been carried out into whether the magnetic fields and radio waves  used during MRI scans could pose a risk to the human body.

No evidence to suggest that there is a risk has been found, which means that MRI is one of the safest medical procedures currently available.

Last reviewed: 29/11/2011

Next review due: 29/11/2013

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Comments are personal views. Any information they give has not been checked and may not be accurate.

dianexx said on 25 April 2013

hi, i had a mri scan on my right knee yesterday, i was a bit nervous bout haveing it done, theres nothing to worry about i was only in there for 20 mins theres abit of noise, take an cd with you to listen to.

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susieh13 said on 03 August 2012

Just got home from having an MRI at the John Radcliffe Hospital in Oxford, and have to say, as a claustrophobia sufferer, it was not as bad as I feared. I did keep my eyes closed the whole time, as, although there was a picture to look at, I could not see it properly without my glasses, so waste of time. The noises were a bit off-putting at the beginning but I started counting to myself, but soon gave up as I kept getting lost anyway. I had taken a Diazapam before I went, so I suppose that did help. All in all, not too bad, and I would not be so scared next time.

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milly j said on 15 May 2012

got my mri scan 2moz scanning my lower back bit nervous but readin these reports made me feel a bit more relaxed

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CathieG said on 04 June 2011

This is a quick down to earth explanation. For further information there are tabs near the top of the page for more in-depth facts for those who need them.

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rrsheard said on 15 February 2011

Far too short and lacking in information. Maybe should have links to more info

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CT scan

A CT scan uses a series of X-rays to produce very detailed pictures of the inside of your body