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Overview
Magnetic Resonance Imaging (MRI) is a non-invasive test that uses magnets and radio waves to create detailed images of the inside of your body.
Magnetic resonance imaging helps doctors diagnose and monitor many conditions, including injuries, tumors and problems with the brain, spine or joints. It does not use radiation and can be used to find and see tissue changes throughout the body.
The MRI scanner is a tube surrounded by a giant circular magnet. You are placed on a moveable bed that is inserted into the scanner.
Preparing for your MRI
Take your regular medications as prescribed. Bring a list of all current medications to your appointment.
Take insulin as directed. You may have a light meal after taking it.
Tell staff if you have any allergies to medications, food or other substances.
Inform staff if you are pregnant or think you might be.
If you’re receiving IV contrast, drink eight glasses of water in the 24 hours before your exam (unless you have fluid restrictions). You may be asked to drink more water after the scan.
You do not need a full bladder. You may urinate before the exam.
Do not bring valuables. A secure storage area will be provided if needed.
Wear clothes without metal zippers or studs. You may be asked to change into a hospital gown.
Remove all metal items including coins, jewelry and hair hairpins, hearing aids, credit cards, watches, keys and dentures or partial plates.
Important safety information
Let staff know if you have any of the following:
- Pacemaker, defibrillator or artificial heart valve.
- Aneurysm clips.
- Cochlear implants.
- History of metal in the eye.
- Neurostimulator (TENS unit).
- Metal implants or infusion devices.
- Tattoos (some inks may contain iron).
- Past injuries involving bullets, shrapnel or metal work exposure.
Some implants are MRI-safe, but all devices must be reviewed using clinical and manufacturer information before your scan. In some cases, an X-ray may be needed to check for metal.
Understanding contrast agents
Contrast agents are used during some MRI scans to help highlight specific areas of the body and improve the clarity of the images.
For most patients receiving an MRI with contrast, no special preparation is needed. However, if you are 70 years of age or older, or have certain medical conditions, your doctor will send recent blood work to help assess how well your kidneys can handle the contrast agent. These conditions will be discussed when your appointment is booked and are also part of the questionnaire you’ll complete on the day of your exam.
Once the exam is complete, you’ll be asked to wait in the recovery area for about 30 minutes. This observation period helps ensure that any signs of an allergic reaction are noticed and addressed. Allergic reactions to MRI contrast are extremely rare.
If you are receiving contrast
Before the scan begins, a technologist will insert an intravenous (IV) line into a vein in your hand or arm. This feels similar to having blood drawn.
The contrast agent will be injected through the IV after some initial images are taken. It’s normal to feel a brief coolness or flushing sensation when the contrast is injected.
Additional images will be taken during or after the injection.
During your MRI
When you arrive for your MRI, you’ll be positioned on a table that slides into the scanner. Small devices may be placed around the area being scanned to help capture clear images. You’ll be asked to stay as still as possible during the exam—sponges and supports may be used to help you hold the correct position comfortably.
The MRI machine makes loud knocking or tapping sounds while it takes images. You’ll be given earplugs or headphones to reduce the noise. The exam itself does not hurt.
A technologist will monitor you throughout the procedure. You’ll be able to speak with them at any time using a call bell or intercom. If you’re having a head scan, a mirror may be used so you can see outside the machine.
Frequently asked questions (FAQs)
After your MRI
You may feel very well rested since you’ve just been lying on a table and doing absolutely nothing! (In fact, some people even fall asleep during the exam.) Other than that, you’ll feel perfectly normal and can go back to your everyday activities.
If you have further questions about your MRI exam, the MRI technologist or your doctor will be glad to answer them.
There are no known side effects of MRI. There is no radiation and the test has no known long-term effects.
Getting your results
After your MRI scan, a radiologist—who is specially trained to interpret medical images—will carefully review your results. This process takes time, as the radiologist needs to examine all the images and compare them with any previous tests you may have had. For this reason, results are not available immediately after your exam.
The results of your scan will remain confidential. All hospital staff are bound to confidentiality guidelines and follow strict codes of professional conduct.
Your referring doctor will receive a report, usually within two to seven days of your exam. If you have questions about your results, you can contact your doctor directly to discuss them.
MRI Central Intake Program
Doctors within the Champlain Region are asked to follow the new process for requesting non-urgent MRI scans for outpatients.