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Magnetic Resonance Imaging (MRI)

What is magnetic resonance imaging?

Magnetic resonance imaging (MRI) produces detailed images of the body using a very strong magnet and radio waves. It does not use radiation. The part of the body being examined is centred inside a tunnel that creates a magnetic field. Since our bodies are mostly made up of water, when we lie down in a strong magnetic field, the hydrogen atoms in the water “line up” with the magnetic field, much like a compass pointing north. Radio waves cause the atoms to emit signals that a computer will measure and create pictures of the body part being examined.

Person getting an MRI

While MRIs are generally safe, the magnet used during the test means people with certain implanted devices, such as pacemakers or cochlear implants, may not be able to have the test. Alternative imaging should be discussed with your doctor.

Getting an MRI: what to expect

Preparing for the test

Different tests require different preparations. It’s very important the correct preparation is used for the test to be performed properly. For example, an abdominal or pelvic scan may require you to not eat or drink for six hours before your test. Another test may not have any restrictions.

For all MRIs, please consider the following:

  • Wear clothing (including undergarments) made of cotton and free of metal. Zippers, clasps, wires and some threading can interfere with the MRI.
  • Remove make-up and all jewellery, including piercings.
  • Leave valuables at home. Sunnybrook is not responsible for personal belongings.
  • If applicable, bring extra transdermal patches and continuous glucose meters (CGM) to apply after your examination. Patches will be removed before your MRI.

If you are scheduled to have an MRI at Sunnybrook and are not sure of how to prepare for it, please call 416-480-4336.

If you are concerned about closed spaces, discuss with your doctor the possibility of getting a prescription for oral sedation that you will take after you arrive for your test to help relax you. However, most patients who are nervous do not end up taking sedation after speaking with our technologists. We’ll do our best to keep you comfortable.

» Watch the video: How to prepare for an MRI scan

On the day of the test

The test will take approximately one to two hours, including time to prepare.

Please check-in for your appointment at the Bayview Campus (2075 Bayview Ave), A-wing, ground floor, room AG 256.

After check-in, you’ll be taken to a room to prepare for the test. Our staff will ask you a number of MRI safety screening questions, including your medical history, current medications and allergies. You can also ask any questions you may have about the procedure.

Our staff will assess your clothing to determine if you need to change into a hospital gown. You will be asked to remove the following: your watch, jewelry, wallet (credit cards with magnetic strips can be erased by the magnet, change can be attracted to the magnet).

For your safety, only the approved personal clothing or hospital gown should be taken or worn into the MRI suite. Items such as hearing aids, artificial limbs/braces, or items stuck to the skin must be removed. Please ask the technologist if you are unsure about any particular items.

During the test

The technologist will help you lie in the correct position on the examining table. The table will then be positioned into a five-foot long tunnel so that the body part being scanned is in the centre. Depending on the scan, a good portion of your body may be outside of the tunnel.

The scan can be loud, so you’ll be given hearing protection. As the MRI scan begins, you will hear the equipment making a muffled thumping sound. You shouldn’t experience any pain with this test, however you may feel a little warm. In the unlikely event you do feel pain or discomfort, it is important to let the technologist know immediately during the procedure so they may assess your situation. You can alert the technologist by squeezing the emergency call bell that you will have in your hand during the MRI procedure.

It is important that you lie as still as possible during the procedure so that your images are as clear as possible.

» Read tips for managing claustrophobia during your MRI scan

After the test

Generally, you can resume your usual activities and regular diet immediately after the test. If you have taken a sedative, you must have a friend or family member drive you home.

The results of your magnetic resonance imaging should be available to your referring physician within 10 business days after your test. Your physician will discuss the test results with you.

Your report can also be accessed through MyChart in two to three weeks after your test.


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Location and contact

Magnetic Resonance Imaging (MRI)

Sunnybrook Health Sciences Centre
2075 Bayview Avenue,
A-wing, ground floor, room AG 256
Toronto, ON M4N 3M5

Phone: 416-480-4336

MRI services are available at our Bayview Campus by pre-scheduled appointment only.

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