Magnetic Resonance Imaging (formerly known as Nuclear Magnetic Resonance Imaging - NMRI) is a type of medical imaging whereby non-ionizing radiation is used to recreate detailed anatomical imaging of the human body. MRI is now one of the most powerful diagnostic tools in the evaluation of soft tissue pathologies.

MRI is the method of choice for the diagnosis of many types of injuries and conditions because of the incredible ability to tailor the exam to the particular medical question being asked. By changing exam parameters, the MRI system can cause tissues in the body to take on different appearances, and thus differentiate normal form abnormal tissues.
 
The fact that MRI systems do not use ionizing radiation is a comfort to many patients, as is the fact that MRI contrast materials have a very low incidence of side effects. Another major advantage of MRI is its ability to image in any plane, which increases the number of ways the radiologist can view an image. 

How does it work?

The human body is composed of 60-70% water. Water molecules contain hydrogen and oxygen atoms. The Hydrogen nuclei (protons) contain magnetic properties due to the fact that they are charged particles that spin. A MRI machine produces a strong magnetic field, along which these protons align themselves. A second magnetic field in the form of a radiofrequency pulse is applied (at a right angle), which causes the protons to gain energy and change direction. The MRI scanner produces an image by reconstructing information from several such magnetic fields applied throughout procedure.

What can I expect when I am inside the machine?

Loud knocking sounds – these are created when the coils are turned on and off to help produce the image. This is normal and ear plugs will be provided to help block this noise.

Some persons who suffer from mild claustrophobia may feel slightly anxious during the scan due to the small tunnel through which they are taken to the center of the machine to do the scan. To combat this, several techniques are used during the scan, such as closing your eyes and listening to music will help, other techniques will be explained beforehand. If you are claustrophobic, we recommend that you ask your doctor to prescribe a sedative for you before the test.

MRI scans require patients to hold very still for extended periods of time. MRI exams can range in length from 20 minutes to 90 minutes or more. Even very slight movement of the part being scanned can cause very distorted images that will have to be repeated.

Can I do the scan if I am pregnant?

There are no effects of MRI on pregnant women. However, current guidelines dictate that scans undergone during pregnancy should only be done if essential. It should be noted that during this period contrast agents are absolutely avoided.

Will it cause any harm?

MRI scans fall under the category of non-ionizing radiation. Thus there are virtually no biological side-effects from this type of radiation. However, death and injury may occur from the creation of projectile objects when the magnetic field is applied in the presence of any metal objects. Please provide a full and accurate response to all of the medical history questions asked by our MRI technician

What are some of the objects that may be hazardous or interfere with the MRI examination?

• Cardiac pacemakers
• Aneurysm clips
• Heart valves
• Artificial limb/joint
• Intra-uterine devices
• Hearing aids
• Dentures
• Tattoos

 
A Complete list of all the possible hazardous objects will be made available to you before the examination. If you have any queries, please do not hesitate to ask the technician before proceeding with the examination.