How Does MRI Work?

MRI utilizes the physical properties of magnetic fields, radio waves and computers to generate images of the tissues within the body. MRI signals from the body are generated using a safe magnetic field in combination with radio waves of a specific frequency. The MRI signals are detected and converted to a form which the computer can understand. The computer processes the MRI signals from the body to form the MR images. Different tissue characteristics are revealed through this process and are thereby translated into different contrast levels on the MR images. The trained physician can then view the MR images and form a clinical diagnosis.

What does the patient experience when being imaged with MR?

The MRI procedure will typically last anywhere from 30 to 90 minutes, depending on the type of information required by the physician. To conduct the MR study, a technologist will assist the patient onto a padded, moveable scanning table. The table and patient are positioned inside the opening of the MRI scanner. The patient is easily observed by the technologist throughout the study, and is able to speak with the technologist or ohvsician at any time. The patient is only required to remain as still as possible during the exam. During the scan, the patient experiences nothing unusual. A variety of sounds, such as humming and thumping noises, will be heard as the scan progresses. This is normal, and a sign that the exam is proceeding as required. After the exam, the patient may resume all normal activities.

How does a patient prepare for an MR scan?

In the days before the MRI scan, a patient may follow all normal routines, such as eating and taking regular medication. Immediately prior to the MR scan, the technologist or physician will provide an explanation of the MR process. The patient is asked to remove any metal objects, such as jewelry or non-permanent dentures. Any metal object might be attracted to the MR scanner's magnet, and thereby hinder the procedure. Bank cards and credit cards are also restricted from the scan room, as the magnetic field could erase the information contained on them. As a final precaution, the patient will be asked a series of questions to insure that there are no metal or electrical objects inside the patient.