Magnetic Resonance Imaging (MRI) uses a magnetic field and radio waves instead of X-Ray to display many parts of the body, especially the brain, spine and joints.
Patients are asked to lie on a table and remain still for approximately 15-20 minutes, depending on the test ordered. We allow up to 30 minutes for the exam yet most take only 15-20 minutes.
During the examination, a knocking sound will be heard, which is normal and is the operation of the imaging process. The MRI process captures different tissue characteristics and translates them into different levels of brightness on the image.
It's important to lay still during the exam since movements could distort the image quality, and sequences of the exam would have to be redone.
The Exam usually takes 15 to 40 minutes. It consists of taking several images lasting 5 to 10 minutes each.
You'll be asked to remove eyeglasses, watch, jewelry, credit cards, dentures, hearing aids, wigs (removable hair extensions) and any other metallic objects you are carrying.
Then, the technologist will help you lie down on a cushioned table. A device called a 'coil' will be placed over or under you. It helps the MRI system create a clear picture of your body. When you are comfortably positioned, the table will move under the magnet. The technologist will then step into the control area, while staying in constant contact with you both visually and through an intercom. As the exam proceeds, you will hear a muffled thumping sound for several minutes at a time. Relax and try to lie as still as possible. Any movement during this time will blur the picture. When the exam is done, the technologist will help you off the table.
No special preparation is needed. Eat normally and take medication as usual, unless your doctor has given you other instructions. You may find it easier to relax if you avoid drinking coffee or other caffeinated beverages before the exam.
Magnetic resonance imaging is very safe. There are no health risks associated with the magnetic field or the radio waves used by the machine.
However, some special circumstances limit the use of magnetic field, so it is important for you to tell us if any of the following apply to you or someone accompanying you into the exam room:
Any metallic substance on your person can affect the quality of the diagnostic images. It can also cause discomfort or injury to you when placed in the magnetic field, and may exclude you from the exam.
In most cases an MRI exam does not require any injections. In some situations, however, a substance known as a contrast agent may be needed to enhance the ability of the MRI to see into your body. All contrast agents are FDA-approved and are considered safe.
Very anxious patients and small children may opt for sedation to help them relax and lie still during the exam. If you think you will require a sedative, you will need to obtain this from your doctor. You will need someone to drive you home.