MRI Scan
| Overview |
MRI Scan Overview
Magnetic resonance imaging (MRI) uses a magnetic field and energy pulses to create images of specific organs and structures in your body. The machine used for an MRI is very large. You either place your whole body into a special compartment, or just part of your body, such as your knee, ankle, or elbow.
Because this test can make people feel claustrophic, CML HealthCare offers both Open and Closed Magnetic Resonance Imaging (MRI) services in various cities throughout Canada. The difference between an open MRI and a closed MRI is that one machine has a doughnut-shaped tube, which fully encloses the patient, and the other is open on all four sides. For people who suffer from anxiety and claustrophobia, the open-gantry style is a more comfortable option. CML HealthCare offers MRI services in Vancouver, Victoria, Ajax, Mississauga, and Open MRI in Calgary.
CML HealthCare clinic. MRI machine.
Click here to see images from other CML HealthCare locations.
MRI Scan FAQs
How often should an MRI scan be performed?
This test is done as needed when a doctor requires a detailed cross-sectional image of the inside of your body.
Why is an MRI scan performed?
Because an MRI scan creates detailed images of the body, doctors use this test as a tool to identify problems in people with various symptoms or conditions. It also shows blood clots, brain damage, and nerve damage (such as that which occurs in multiple sclerosis). The test can also detect damage to the heart and lungs, reproductive system, bladder, bones and joints (such as that which occurs with arthritis), and spine.
Sometimes the technologist will inject a special dye (also called contrast material, contrast dye, or contrast medium) into your arm. This makes the images of any damaged or abnormal tissue clearer.
Are there any risks or precautions with an MRI scan?
The powerful magnetic field and pulses of energy used during an MRI do not hurt or damage your body or cause cancer. However, the magnet can damage certain pacemakers, artificial limbs, and other metallic medical devices. Unsecured metal objects (such as watches or jewelry) must be removed prior to the scan or they will be rapidly pulled toward the magnet, potentially causing serious injury.
The dyes used to provide clearer MRI pictures have a slight risk of causing allergic reactions. It's important to tell your doctor and the radiologist if you have allergies of any kind, particularly to contrast dyes.
If you have any metal objects in your eye, tell your doctor or the person performing the test, because the magnetic field may cause metal pieces to move and possibly damage your eye. The effects of MRI tests on unborn babies are not known, so be sure to inform your doctor or the person performing the test if you are or may be pregnant.
If you are taking any medications in the form of a patch, make sure to tell your doctor beforehand. Because patches with an aluminum or foil backing can react during the MRI test, leading to skin burns, they should be removed before the MRI test.
What happens during the MRI?
For an MRI, you remove your clothes and put on a paper gown. Then you lie face-up on a table that slides into a narrow tunnel that contains the strong magnetic field. The test usually lasts between 15 to 90 minutes, and you must lie still the entire time.
During the test, the magnet in the machine moves from side to side, making loud noises for minutes at a time. If you are bothered or disturbed by loud noises, try wearing earplugs for the test. It is extremely important that you remain still in order to achieve the most accurate images possible.
To ensure your comfort, you will be in constant contact with the technician via intercom during the exam. If you are really concerned about the test, your doctor may prescribe a sedative for you to take beforehand.
How should I prepare for an MRI scan?
If your doctor tells you that you need to have an MRI, there are certain things you'll be asked about before having the test. Let your doctor know if you:
- are uncomfortable in small spaces;
- have a pacemaker, artificial heart valve, artificial limb, cochlear implant, dental implants, metal implants or pins, or any other implanted or prosthetic medical device;
- have worked in areas with metal, such as in factories;
- are pregnant, or think you might be pregnant;
- have an allergy of any kind (the dyes used during an MRI can cause serious allergic reactions in some people with pre-existing allergies, including those involving hay fever, hives, or asthma, as well as food or medication allergies);
- have an intrauterine device (IUD);
- have a medication patch on your skin (the patch may burn during the test if not removed); or
- have any medical conditions (people with certain conditions should not be given the MRI test dyes).
Tell your doctor or pharmacist about all prescription, over-the-counter (non-prescription), and herbal medications that you are taking. Also tell them about any medication allergies and medical conditions that you may have.
Ask your doctor or pharmacist whether you need to stop taking any of your medications before the test.
What can I expect after the MRI?
After the test is done, the radiologist may discuss preliminary results. No pain or other sensations normally occur after an MRI. You can return to your usual activities once the test is complete.
MRI Scan Results
A radiologist reviews and interprets the images from an MRI scan. Full results are usually available a couple of days later, and your doctor will discuss these results both with the radiologist and you.
Click here for an MRI requisition form
