Diagnostic MRI
TECHNOLOGY
Magnetic resonance imaging (MRI) is an advanced imaging technology that visualizes the internal structures and soft tissues
of the body. It uses a strong magnetic field and radio waves to produce highly detailed images of the body, which are reconstructed by a computer. MRI is a very safe imaging technique with no radiation exposure.
APPLICATIONS
Brain/Head
MRI is excellent for assessing the brain and spinal canal. It is used to detect brain abnormalities, tumours, strokes and neurological diseases such as multiple sclerosis. It can also identify disorders of the pituitary gland, vision pathway and inner ear.
Spine
MRI is most commonly used to detect bulging, degenerated or herniated intervertebral discs. For patients who have had lower back surgery, MR with contrast is the best tool to distinguish recurrent disc problems versus scarring.
Joints
For joints (ankles, elbows, knees, hips, shoulders, wrists), MRI provides detailed assessment of soft tissues and anatomical structures. Abnormalities and injuries of the ligaments, tendons, cartilage and bones can be accurately detected.
Abdomen
MR with contrast rivals CT in assessment of solid organs such as kidneys, liver, spleen, pancreas, and reproductive organs. It can detect or rule out cancerous tumours and characterize and stage diagnosed tumours, determining the size, extent and spread.
Angiography
MR angiography is a non-invasive way to assess blood vessels. It can diagnose and characterize cerebral aneurysms, investigate peripheral atherosclerosis (e.g. poor circulation in extremities) and evaluate strokes.
PRE-SCREENING CONSIDERATIONS
Ability to hold still - Patients are required to lie still for periods of 10 minutes or more to prevent blurring of images. A cough or severe pain can negatively affect the quality of the results.
Ability to hold breath - MRIs of the abdomen require breath holds of up to 30 seconds.
Body piercing - All piercing needs to be removed prior to the MRI.
Dental work - Dental implants and fillings are safe for the MRI, as are braces. Some image distortion is possible if we are imaging the head; please discuss with us when you are booking your appointment.
Implanted devices - Orthopedic prosthesis, pins, plates and surgical clips are generally safe if they were inserted more than six weeks before your appointment date. In some cases, our radiologist may need to review your operative report to determine the MRI compatibility of your implanted devices.
Metal body in the eye - Patients who have ever been a grinder, metalworker or welder, or have had a metallic foreign body in their eye, might require an x-ray of the eyes prior to the MRI.
Pregnancy - Although there are no known hazards related to pregnant women who have had an MRI scan, we ask that female patients who may be or are pregnant speak to us specifically prior to considering a scan.
Tattoos - Due to the metallic element in certain inks, patients with tattoos (including cosmetic) may experience a slight warming sensation at the tattoo sites.
Weight/Girth - The MRI measures two feet wide (60 centimeters) with a maximum weight capacity of 360 pounds (163 kilograms). Extremely large patients may not be able to have an MRI.
CLAUSTROPHOBIA
The MRI is a tunnel about four feet long, two feet wide and open on both ends. The interior of the magnet is well lit and ventilated and an intercom allows you to have contact with the technologist at all times. We also provide you with soft earplugs or play music during the scan.
Most patients do not experience claustrophobia, but if you are concerned, please mention this to our staff at the time of booking. We will be happy to discuss ways you can minimize the effects of claustrophobia.
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NOTE TO PHYSICIANS
Please review the list of contra-indications and pre-screening considerations before referring your patients for an MRI.
If you or your patients are concerned about claustrophobia interfering with the MRI examination, you may want to consider prescribing the oral or sublingual benzodiazepine of your choice. Please ensure your patient takes the medication one hour prior to their appointment time, and that they can arrange a ride to and from their appointment. Claustrophobia is rarely severe enough (0.2% of patients) to require IV sedation, which we do not offer in our facility.
Certain examinations require the intravenous MR contrast agent, gadolinium, which is very safe, and contraindicated only if there is a history of previous reaction to gadolinium, or active asthma.
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SAFETY
A MRI is a non-invasive procedure that is not painful and involves no radiation. It sometimes requires an intravenous contrast (dye) to be used, which is exceptionally safe.
YOU CANNOT HAVE AN MRI IF YOU HAVE:
Cardiac pacemakers
Brain aneurysm clips
Neurostimulators
Cochlear implants or other implanted electromagnetic stimulators
PLEASE ALERT US IF YOU HAVE ANY OF THE FOLLOWING:
Internal cardiac defibrillator
Implanted infusion pumps (including insulin pumps)
Shrapnel in any part of your body
Metallic coil, stent or filter in a blood vessel
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