Magnetic Resonance (MRI)
Magnetic resonance imaging (MRI) is a diagnostic tool that uses radio frequencies, magnetic fields, and computers to produce cross-sectional images of the soft tissues in the body. These images can be used to aid in the diagnosis of medical conditions. MRI does not use ionizing radiation to produce these images.
MRI exams use electromagnetic fields to produce images, so the presence of items such as surgical implants, metal fragments, and metal piercings could be a safety concern.
Before your exam, an MRI technologist will help determine if these items are magnetic; for example, surgical implants typically have identification numbers that can be used to check their compatibility for MRI tests.
It is important that you inform the clinic if you have any surgical implants or embedded metal fragments when you book your appointment. Note that any piercings will need to be removed before your MRI exam.
What to Expect During an MRI
Before the exam, an MRI technologist will review a safety questionnaire with you to determine whether it is safe to proceed. This will include asking about your surgical history and any injuries involving metal, such as having metal fragments removed from your eyes.
Following the safety questionnaire, you will be provided a gown or scrubs to change into before your exam. You will also be given a locker in which to secure your belongings.
The MRI machine produces loud noises as a normal part of its operation. Because of this, you will be given ear protection when you enter the MRI room to dampen the noise produced by the machine during the exam.
You will be positioned on the MRI table. At this point, an additional piece of equipment – called a “coil” – is placed around, over, or under the region of interest in order to produce the image.
Then the table is moved into the MRI tube to position the body region being examined in the middle of the MRI machine. The technologist will monitor you at all times during the exam. You will also be provided with an emergency button so you can communicate with the technologist at any time during the procedure.
Generally, MRI procedures last from 30 to 60 minutes, depending on the body part being examined. It is important that you do not move during the exam - movement will result in blurry images.
In some cases, an intravenous injection of a contrast agent is administered to aid in the diagnosis. The need for contrast is determined by the radiologist. This contrast is injected intravenously in the arm and may cause a cooling sensation.
After the exam is complete, the images are analyzed by one of our radiologists, and a report is sent to your doctor as soon as possible.
- You must provide your complete surgical history, and information on any injuries involving metal, when booking an MRI appointment.
- If you are claustrophobic, please consult with your doctor to see if they would recommend taking anti-anxiety medication before your examination.
- Note that MRI exams performed outside of the hospital is a private service and the cost is not reimbursed by Alberta Health Services.
- Recent studies have shown that some clothing items may contain trace elements that heat up when exposed to magnetic resonance. These items can include underwear with sweat wicking material (silver nitrate) or socks with odour absorbing material (copper). To prevent burns, we may ask you to remove your underwear or socks during the exam. Please note that you will still be provided with scrubs or a gown so you are fully covered.
Planning your next appointment? Learn more about Magnetic Resonance Imaging exam preparation and get directions to our MRI clinic.