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MRI scan

An MRI scan creates pictures using magnetism and radio waves. It can show up abnormal areas in the prostate gland.

MRI stands for magnetic resonance imaging. It produces pictures from angles all around the body and shows up soft tissues very clearly.

When you have it

You might have an MRI before a biopsy. This helps doctors see which areas of the prostate to sample.

You might also have an MRI scan if you had a biopsy that didn’t show cancer cells but you have a high PSA level or other symptoms. An MRI can help your doctor to decide if you need a second biopsy.

You normally wait a few weeks before having an MRI after your first biopsy, if this is the case.

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

You can have an MRI scan if you have some metals in your body, but your doctor and radiographer decide if it is safe for you. Tell the scanner staff about any metals in your body.

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. An MRI is generally safe during pregnancy. But as a precaution, you usually won’t have one during the first 3 months of your pregnancy.

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 scan department

The radiographer might ask you to change into a hospital gown. You may 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, keys and bank cards

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 must remove any metal items.

It's also a good idea to use the bathroom beforehand as the scan can take a while. 

In the scanning room

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

MRI scan

You lie on a couch that can slide into the tube. You usually lie down on your back.

You might have an injection of a dye called contrast medium into 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 contrast medium, so your radiographer will ask about any medical conditions or allergies you have. 

Tell the 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.

Once you’re in the right position on the couch, the radiographer leaves the room. They can see you 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. Tell them if you are getting stiff and need to move.

The scanner makes a very loud clanging sound throughout the scan. You’ll wear earphones or headphones to protect your hearing. You can also listen to music. Keeping your eyes closed during the scan 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 tube from the vein in your arm.

You should then be able to go home or back to work and also eat and drink normally.

Getting your results

You should get your results within 1 or 2 weeks. 

Waiting for results can make you anxious. Ask your doctor or nurse how long it will take to get them. Contact the doctor who arranged the test if you haven’t heard anything after a couple of weeks.

You might have contact details for a specialist nurse and you can contact them for information if you need to. It may help to talk to a close friend or relative about how you feel.

For information and support, you can 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.

The contrast medium injection can cause side effects. But these are usually mild and last for a short time.

The effects include:

  • feeling or being sick
  • a skin rash
  • a headache
  • dizziness

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.

There is a risk that the contrast medium will leak outside the vein. This can cause swelling and pain in your arm but it is 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.

Research into MRI scans

Researchers are looking into whether a special type of MRI scan can diagnose prostate cancer. This would mean that fewer men would need a biopsy.

The early results of the PROMIS clinical show many, but not all men with higher risk prostate cancer are diagnosed using MRI and targeted biopsy.  But it also found that some lower grade and even some higher grade cancers were only found using random biopsy.

It is uncertain whether men who have a normal MRI scan can be discharged or if they need to continue to be monitored by PSA testing and another MRI scan or if they should have a biopsy.  

Talk to your doctor about what follow up you need if your MRI scan is normal.

Doctors need to do more research to understand if men with a normal MRI need further monitoring or tests.

Last reviewed: 
06 Jul 2016
  • The Royal Marsden Manual of Clinical Nursing Procedures, 9th, Professional Edition

    L Dougherty and S Lister (Editors)

    Royal Marsden Manual Series, Wiley-Blackwell, 2015

  • Prostate cancer: diagnosis and treatment
    National Collaborating Centre for Cancer, 2014

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