Magnetic Resonance Imaging (MRI)

How magnetic resonance imaging works

MRI uses a powerful magnetic field and radiofrequency waves to produce detailed images of the body’s internal structures. Unlike X-rays or a CT scan (computed tomography), it does not use X-rays. It is based on the properties of hydrogen atoms found in the water molecules of the human body. When exposed to a magnetic field, these atoms emit signals that are captured by the machine and converted into images by a computer system.

The images obtained offer exceptional contrast resolution between different types of tissue, making MRI a particularly effective tool for examining the brain, spinal cord, joints, abdominal and pelvic organs, as well as soft tissues. In certain situations, an injection of gadolinium-based contrast material is needed to better visualize certain lesions or their blood supply.

When an MRI exam is indicated

MRI is indicated in many clinical situations. It is particularly effective for:

• Neurological conditions, to examine the brain, spinal cord, pituitary gland, or cranial nerves, particularly when a tumor, multiple sclerosis, or stroke is suspected;
• Musculoskeletal conditions, to assess injuries to joints, tendons, ligaments, and cartilage, such as a meniscal tear or a rotator cuff injury;
• Spinal conditions, among other things, to investigate herniated discs, spinal cord compression, or degenerative conditions;
• Abdominal and pelvic conditions, including disorders affecting the liver, kidneys, prostate, uterus, or ovaries;
• Vascular conditions, thanks to MR angiography, which can diagnose aneurysms, stenosis (narrowing), dissections, thrombosis, and vascular malformations;
• ENT and cervicofacial conditions, particularly for studying the sinuses, salivary glands, thyroid, pharynx, or the soft tissues of the neck;
• Oncology follow-up, to detect, characterize, and monitor the progression of tumors.

MRI is often used in addition to other imaging exams, such as a CT scan or an ultrasound, to refine a diagnosis or guide a treatment decision.

Preparation before an MRI

Most MRI exams do not require any special preparation. However, certain precautions do apply.

Any implant or metal device in the body must be reported before the exam: pacemaker, prosthesis, surgical clip, stent, metal fragment, or any other implanted device. Some materials are MRI-compatible, others are not. You will be given a pre-exam medical questionnaire to identify any possible contraindications.

For exams involving a gadolinium injection, our team systematically checks your allergy history and confirms the absence of kidney failure when the appointment is booked. In some situations, a kidney function test will be required before the exam.

If you are claustrophobic, let us know when booking your appointment. Appropriate solutions can be considered to ensure your comfort throughout the exam.

Remember to bring your medical prescription as well as the results of any previous imaging exams. They will be useful to the radiologist in guiding the interpretation.

Book an MRI appointment in Montreal

MRI exams are performed by appointment only at our radiology clinic located on Montreal’s South Shore. You can send your prescription by fax to 450-904-0405 or by email to info@radiologiedix30.com. Our team will do everything possible to schedule your appointment quickly. For any other questions, contact us directly.

What to expect during a magnetic resonance imaging exam

MRI exams are performed at the Radiologie Dix30 clinic in Brossard, on Montreal’s South Shore. Please plan to arrive 15 minutes before your appointment time to register at reception and open your file if this is your first visit.

Here is how the exam works:

• Welcome and registration: you present your health insurance card and your prescription. You will be given a pre-exam medical questionnaire to identify any possible contraindications;
• Preparation: you will be asked to remove all metal objects and put on a gown. If a gadolinium injection is planned, an IV line will be placed before the exam;
• Positioning: you lie down on the exam table, generally on your back with a cushion under your knees for comfort. The table then moves inside the machine;
• Image acquisition: the technologist guides you from the control room and gives you all the necessary instructions during the exam. The machine produces characteristic rhythmic noises: earplugs are provided for your comfort. A call bell is available to you at all times to communicate with the technologist;
• Duration: the exam lasts between 20 and 60 minutes depending on the area being examined. It is recommended that you allow at least 30 additional minutes for the entire visit;
• Return to activities: in the vast majority of cases, normal activities can be resumed immediately. If you received a gadolinium injection, be sure to stay well hydrated in the hours following the exam.

Cost of an MRI at the Radiologie Dix30 clinic

MRI exams are not covered by the Régie de l’assurance maladie du Québec (RAMQ). Rates vary depending on the area examined and whether or not a gadolinium injection is required. Consult our fee schedule to find out the cost of your exam.

Results

The exam is generally interpreted within 24 hours after the images are acquired. A detailed report is sent to your referring physician within 2 to 5 days. Your doctor will contact you to share the results and discuss any next steps.