Department of Medical Imaging
Magnetic Resonance Imaging (MRI)
Magnetic Resonance Imaging (MRI) is a non-invasive technique used to look at tissues within the body. This advanced technology can be used to detect abnormalities and disease within the body. It is known for its accurate soft tissue visualization of internal body structures.
An MRI scan is ordered by a physician/specialist who wants detailed images of a very specific part of the body. Whole body imaging is not done. Imaging one specific body part allows for higher quality images.
At RVH, we currently have two MRI machines. One machine uses a large and powerful 1.5 Tesla magnet and the other MRI machine, a 3 Tesla magnet. For this reason, the patient will need to fill out a safety screening questionnaire prior to having the MRI done.
In addition, for patient safety, the patient must remove all metallic objects from their body and should remove all piercings and jewelry prior to coming to the MRI department. All MRI patients will be required to change into a hospital gown and housecoat prior to the MRI examination. Personal belongings are placed in lockers and secured during the MRI examination.
All of our technologists are registered with the College of Medical Radiation and Imaging Technologists of Ontario.
In most cases, you can follow your normal, everyday routine – no special preparation is needed. You will be able to eat and drink normally and take all medications that you are required to take, however there may be some circumstances in which you'll be given specific instructions to follow before the exam. These instructions normally have to do with refraining from eating and drinking for a few hours. Special preparation instructions will be provided to you when your appointment is confirmed by an MRI team member.
Patients are asked to arrive 45 minutes prior to the time they will be placed into the MRI machine. This additional time is necessary to allow for registration and preparation for the scan. The exact arrival time will be confirmed by an MRI team member a few days before your appointment.
Please be aware that during the exam the MR scanner does emit several different noises, such as thumping or banging. It is crucial to remain still during this time in order to get clear images. Hearing protection is provided to patients to dull the noise.
Patient MRI Safety Screening
The many questions asked during the screening process about surgeries and implants are asked to ensure that the patient has had no surgery or injury that would deem the patient unsafe to go into the extremely powerful magnetic environment. Certain types of devices/implants are unsafe to be placed in the MRI environment. Pacemakers and implanted cardioverter-defibrillators (ICDs) are generally considered to be an absolute contraindication to having an MRI study. The MRI scanner can cause damage to such devices, reprogram them, or adversely affect their function in other ways.
Other medical implants have varying degrees of concern in the MRI environment. These concerns are dependent on a number of factors: the strength of the MRI scanner being utilized, the properties of the implant, the scanning protocols and the anatomy being imaged. Medical implants such as nerve stimulators, implanted pumps, cochlear implants, deep brain stimulators and others are often contraindicated for MRI scans. Metallic implants such as surgical prosthesis and aneurysm clips are also potential risks. Safety aspects need to be considered on an individual basis.
IMPORTANT: Medical device patients should always present complete information (manufacturer, model, serial number and date of implantation) about all implants to both the referring physician and to the radiologist or technologist before entering the room for the MRI scan. If this information is not provided or cannot be obtained, the MRI scan will not be scheduled.
There are many medical devices that can be scanned safely with MRI. The MRI department has a variety of safety resources that can be used to ensure the safety of the patient. The referring physician can consult the MRI department if they have concerns about the safety of an implant. Just prior to the patient entering the magnet, the technologist will once again review a detailed series of questions dealing with past surgeries and injuries that the patient has sustained.
THE FOLLOWING ITEMS MAY BE HAZARDOUS OR MAY INTERFERE WITH THE MRI EXAMINATION BY PRODUCING AN ARTIFACT:
|Cardiac Pacemaker or Defibrillator||Aneurysm Clips||Any Type of Biostimulator/ Neurostimulator|
|Artifactual Cardiac Valve||Any Type of Intravascular Coil, Filter or Stent||Any Type of Electronic, Mechanical or Magnetic Implant|
|Any Type of Internal Electrode(s), Including Pacing Wires ||Cochlear Implant||Any Metallic Foreign Body: Shrapnel/Bullets|
|Vascular Access Port (Port-A-Cath, Swan-Ganz Catheter)||Intraventricular Shunt||Any Metallic Fragments in eyes (Grinding or Welding)|
|Any Type of Surgical Clip or Staple(s)||Any Implanted Device or Prosthesis (Infusion Pump/Orthopedic, Penile/Orbital Prosthesis)||Halo Vest or Metallic Cervical Fixation Device|
FERROMAGNETIC FOREIGN BODIES
(such as bullets, shrapnel fragments and metal pieces in the eye from grinding/welding)
These must be investigated prior to the patient being scanned. The ordering physician should have orbital x-rays performed on anyone suspected of having metal fragments in their eyes. Interaction of the magnetic and radio frequency fields with metal objects can lead to trauma due to movement of the object in the magnetic field or thermal injury from heating of the object.
Although MRI scanners are shorter and wider than in the past, some patients can experience a claustrophobic sensation as they lie inside the MRI scanner. For this reason, patients with any history of claustrophobia should relate this to the physician who is requesting the test. The ordering physician can provide the patient with a mild sedative to be taken prior to the MRI study. The sedation will help to alleviate the nervous feeling caused by claustrophobia and allow the patient to better cope in the MRI machine. The doctor/pharmacist will give the patient information on when to take the sedation and should reinforce with the patient that he/she should not drive.
Please note: Sedation will not be provided by the Royal Victoria Regional Health Centre.
Some ways to prepare in advance include:
• Practice visualization/relaxation techniques
• Discuss your fears with your physician and have sedation prescribed
• Ask a member of the MRI team if you can be examined in a feet first position (for some examinations your head will be out of the scanner)
During the MRI Study
During the MRI study, MRI technologists will be nearby throughout the entire procedure. Furthermore, there is always a means of communication with the staff. The patient will hold on to a buzzer which can be squeezed if the patient requires assistance and cannot tolerate the scan. If pressed, the technologist will immediately assist you.
The patient may also find the following techniques helpful:
• Close your eyes and/or cover your eyes (e.g., washcloth, eye mask)
• Listen to music on headphones (bring a CD or IPOD with you)
• Remind yourself about the importance of this study
• Verbally communicate (every few minutes) with the MRI technologist through an intercom system
• Utilize visualization/relaxation techniques