MRI brain scan

  –    Overview
  –    What happens during my MRI scan?
  –    Who can have an MRI?
  –    How do I prepare for my MRI?

Overview

Magnetic resonance imaging (MRI) is a type of scan that uses 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 powerful magnets. You lie inside the tube during the scan. While an MRI scan can be used to examine almost any part of the body, we will only be getting images of your brain.

It's very important to keep as still as you can during your MRI scan. 

MRI

What happens during my MRI scan?

During your MRI scan, you will lie on a flat bed that's moved into the scanner. You will be given a squeeze ball that you can use to alert the study staff if you begin to feel uncomfortable. 

At certain times during the scan you will be able to listen to music and close your eyes, while other times we need to turn the music off and have you open your eyes.

You may also be given a box with buttons before entering the MRI. This will be used for some tasks that take place during the scan.

Throughout your MRI, the scanner will make loud tapping noises. This is the electric current in the scanner coils being turned on and off. 

The scan will last between 60 to 75 minutes, depending on which study you are participating in and how many images are taken.

Who can have an MRI?

An MRI scan is a painless and safe procedure. You may find it uncomfortable if you have claustrophobia, but most people are able to manage it with support from the study staff.

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 has been found to suggest there's a risk, which means MRI scans are one of the safest medical procedures available.

But MRI scans may not be recommended in certain situations. For example, if you have a metal implant fitted, such as a pacemaker or artificial joint, you may not be able to have an MRI scan.

Metal implants or fragments

Having something metallic in your body doesn't necessarily mean you can't have an MRI scan, but it's important for the study staff carrying out the scan to be aware of it.

They can decide on a case-by-case basis if there are any risks, or if further measures need to be taken to ensure the scan is as safe as possible.

You may need to have an X-ray if you're unsure about any metal fragments in your body, especially if you're unsure about possible metal fragments in your eyes.

Examples of metal implants or fragments include:

  • a pacemaker – a small electrical device used to control an irregular heartbeat
  • an implantable cardioverter-defibrillator (ICD) – a similar device to a pacemaker that uses electrical shocks to regulate heartbeats
  • metal plates, wires, screws or rods – used during surgery for bone fractures
  • a nerve stimulator – an electrical implant used to treat long-term nerve pain
  • a cochlear implant – a device similar to a hearing aid that's surgically implanted inside the ear
  • a drug pump implant – used to treat long-term pain by delivering painkilling medication directly to an area of the body, such as the lower back
  • brain aneurysm clips – small metal clips used to seal blood vessels in the brain that would otherwise be at risk of rupturing (bursting)
  • stents, filters and vascular coils – small metal devices that are surgically implanted in blood vessels
  • metallic fragments in or near your eyes or blood vessels (common in people who do welding or metalwork for a living)
  • prosthetic (artificial) metal heart valves
  • penile implants – used to treat erectile dysfunction (impotence)
  • eye implants – such as small metal clips used to hold the retina in place
  • an intrauterine device (IUD) or coil – a contraceptive device made of plastic and copper that fits inside the womb
  • artificial joints – such as those used for a hip replacement or knee replacement
  • dental fillings and bridges
  • tubal ligation clips – used in female sterilization
  • surgical clips or staples – used to close wounds after an operation
  • tattoos or permanent make-up
  • objects such as bullets or shrapnel
  • breast expanders – used after a mastectomy
  • insulin pumps and glucose monitors – electronic devices used by some people with diabetes

Tattoos

Some tattoo ink contains traces of metal and can become hot in an MRI. If you have a tattoo on your face or neck, we may not be able to scan you. 

Tell the study staff immediately if you feel any discomfort or heat in your tattoo during the scan.

How do I prepare for my MRI?

Your safety and comfort is our top priority. Metal and products that contain metal must be removed before the scan.

On the day of your scan, the study staff will go over an extensive metal checklist with you to ensure that no metal is brought into the MRI scan room.

Please assist our staff with this process by using the following guidelines to prepare for your MRI.

Metal

You will be asked to remove jewelry, belts, bobby pins, makeup, credit cards, cell phones, splints, braces, wrap bandages or any other metal objects that might interfere with the magnetic field of the MRI scanner.

Please notify the study staff prior to your appointment if you may have any metallic material in your body such as surgical pins, plates, clips, IUD, or any other foreign objects.

To assist with the metal screening process, please avoid bringing any metal objects that you will not need that day such as lighters or pocket-knifes.

Clothing

Please wear something comfortable to your appointment. You will be required to change into scrubs before the scan. Do not wear headbands or hair binders.

Undergarments

If you wear a bra, please wear a sports bra or a bra that does not have any underwires. If you wear an underwire bra on the day of your scan you will need to remove it.

Tattoos

Please notify the study staff of any tattoos you have on your body, especially if they are on your head, face, or neck.

Jewelry and piercings

Please remove all body piercings (ears, nose, belly) prior to your MRI appointment. We cannot scan you unless all piercings are removed.

You must also remove all jewelry (rings, necklaces, bracelets, watches) before entering the MRI scan room. While you may wear jewelry to the appointment, it is preferred that you leave these items at home.

Transdermal skin patches

Any transdermal patches (birth control patch, nicotine patch, GTN patch, fentanyl patch) must be removed for the MRI scan.

Please consult your care team prior to removing the patch.

Inform the study staff if the patch cannot be removed. We will not scan you with a transdermal patch in place.

Makeup and hair care

Please do not wear the following items to your appointment:

  • nail polish – all fingernail polish, especially metallic shades, and any metallic toenail polish will need to be removed
  • makeup – do not wear makeup to your appointment, especially eye makeup of any type; we will require you to remove it before the scan
  • hair products – gels, mousse, hairspray, and products that contain heavy amounts of mineral oil are not recommended
  • hair accessories –  bobby pins, clips, hair ties, and headbands
  • artificial eyelashes
  • permanent eyeliner – our staff cannot scan you if you have permanent eyeliner
  • hair extensions or wigs

It is best if you arrive with clean dry hair. Please try to wash your hair the evening before or the morning of the scan.

Pregnancy

Although there are no known risks associated with pregnancy, we will not scan someone who is pregnant.

Please inform study staff if there is a possibility you may be pregnant. We will do a urine pregnancy test prior to your MRI scan if you are a woman younger than 45.

Hydration and liquids

Try not to come to the scan in a dehydrated state.

You can drink your usual amount of caffeine throughout the day, but you will not be allowed to use the bathroom in the middle of the scan. Try not to drink large quantities of liquid before entering the MRI.

Sleep

It is difficult to remain still in the MRI when you are very tired. Try to get a full night’s sleep the night before your appointment.

Drugs and alcohol

Our study staff will not scan you if they feel that you are under the influence of recreational drugs or alcohol. You will do a drug and alcohol screening prior to the scan. Please do not arrive with a hangover.

Vision

If you wear eyeglasses or contacts, you will be asked to remove them during the scan for your safety. Please bring your prescription details with you, and our study staff will provide you with MRI-safe glasses that you can wear during the scan.



Last Updated: 3/3/2023