MRI scan for acute lymphoblastic leukaemia (ALL)

MRI stands for magnetic resonance imaging. It creates pictures using magnetism and radio waves.

MRI scans produces pictures from angles all around the body. 

You don't often have an MRI scan for ALL. But there might be certain situations were your doctor might want you to have one. For example if you have symptoms that suggest that you might have:

  • leukaemia that has to spread to the central nervous system (CNS) Open a glossary item
  • bleeding in the CNS

Symptoms might include headaches, feeing or being sick, seizures (fits), dizziness, unsteady when walking, changes to eyesight, weakness in your arms or legs and changes to your speech. 

Preparing for your MRI scan

Before you go to your appointment, or when you arrive, you fill in a safety checklist. This asks about:

  • any operations you have had
  • whether you have any metal implants or other metals in your body

An MRI scan uses strong magnetism which could affect any metal in your body. These include:

  • pacemakers or an implantable defibrillator (to treat abnormal heart rhythms)
  • surgical clips, pins or plates
  • cochlear implants (for deafness)
  • metal fragments anywhere in your body – for example from an injury

Some people feel claustrophobic or closed in when they’re having an MRI scan. Contact the department before your test if you’re likely to feel like this. The hospital staff can take extra care to make sure you’re comfortable and that you understand what’s going on. Your doctor can give you medicine to help you relax if you need it.

Tell the department staff beforehand if you think you’re pregnant. 

Eating, drinking and medicines

You might need to stop eating and drinking an hour or more before the scan. Talk to your doctor if this could be a problem, for example if you're diabetic.

You can usually take all your medicines as normal beforehand.

Some stick-on medicine patches contain metal and could overheat in the MRI scan, causing burns. Tell your radiographer beforehand if you use medicine patches. You might need to remove them before the scan.

What to expect

When you arrive at the scanning department, the radiographer might ask you to change into a hospital gown. You might not have to undress if your clothing doesn’t have any metal, such as zips or clips. 

You have to:

  • remove any jewellery, including body piercings and your watch
  • remove your hair clips
  • empty your pockets of coins and keys

It’s safe to take a relative or friend into the scanning room with you. But check with the department staff first. Your friend or relative will also need to remove any metal they have on them.

In the scanning room

Your radiographer takes you into the scanning room. The MRI machine is large and shaped like a doughnut.

Photograph of an MRI scanner

You lie on your back on a couch that can slide into the MRI machine. 

You might have an injection of a dye (contrast medium) through a small plastic tube (cannula) into a vein in your arm. This helps to show up your body’s organs more clearly. Some people are allergic to the dye, so your radiographer will check first about any medical conditions or allergies you have.

After the dye injection you may:

  • feel sick
  • have a headache
  • feel warm or flushed
  • have a metallic taste in your mouth
  • feel a little dizzy

These effects are usually mild and last for a short time. Tell your radiographer if you feel unwell at any point during or after your scan.

Having the MRI scan

You need to lie as still as possible. The scan is painless but it can be uncomfortable to stay still. Tell them if you're getting stiff and need to move. 

Once you’re in the right position on the couch, your radiographer leaves the room. They can see you on a TV screen or through a window at all times from the control room. You can talk to each other through an intercom.

The couch moves through the MRI scanner. It takes pictures as you move through it. Your radiographer might ask you to hold your breath at times. 

The scanner makes a very loud clanging sound throughout the scan. You wear headphones to protect your hearing. You can also listen to music. Keeping your eyes closed can help.

This 1 minute video shows you what happens when you have an MRI scan.

After your scan

When the scan is over, your radiographer comes back into the room and lowers the couch so that you can get up.

You might stay in the department for about 15 minutes so the staff can make sure you’re okay. Your radiographer removes the cannula from the vein in your arm.

You can then go back to the ward if you are an inpatient or back home. You can eat and drink normally.

Getting your results

Ask your doctor when to expect your results and how you will receive them. 

Waiting for test results can be a worrying time. You might have contact details for a specialist nurse and you can ask them for information. It may help to talk to a close friend or relative about how you feel.

For support and information, you can also contact the Cancer Research UK nurses on freephone 0808 800 4040. The lines are open from 9am to 5pm, Monday to Friday.

Possible risks

An MRI is very safe and doesn’t use radiation. Some people can’t have an MRI but the checklist picks this up beforehand. Your doctor and radiographer make sure the benefits of having the test outweigh any possible risks. The risks include: 

Bruising and swelling

You might get a small bruise around the area where they put the needle in for the cannula. 

There's a risk that the contrast medium will leak outside the vein. This can cause swelling and pain in your arm but it’s rare. Tell your radiographer if you have any swelling or pain. Let your GP know if it doesn’t get better or starts to get worse when you’re at home.

Allergic reaction 

An allergic reaction to the contrast medium injection is rare. This most often starts with feeling weak, sweating and difficulty breathing. Tell your radiographer straight away if you feel unwell so they can give you medicine to control the reaction.

Last reviewed: 
01 Jun 2021
Next review due: 
01 Jun 2024
  • Safety Guidelines for Magnetic Resonance Imaging Equipment in Clinical Use
    Regulating Medicines and Medical Devices (MHRA), February 2021

  • The Royal Marsden Manual of Clinical Nursing Procedures, Professional Edition (10th Edition)
    S Lister, H Hofland and H Grafton
    Wiley-Blackwell, June 2020

  • Clinical guidance for MRI referral
    Royal Australian College of General Practitioners, 2013

  • Handbook of MRI scanning
    G Burghart and C Finn
    Elsevier Mosby, 2011

  • BMJ Best Practice Acute lymphocytic leukaemia
    BMJ Publishing Group Ltd, last updated March 2021

  • The information on this page is based on literature searches and specialist checking. We used many references and there are too many to list here. Please contact with details of the particular issue you are interested in if you need additional references for this information.

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