Magnetic resonance imaging (MRI) is a perfectly safe, non-invasive procedure used to create images of tissues in your body. Your doctor may order an MRI to assist in diagnosing an injury or health condition. In some instances, it can monitor the progress of your recovery. An MRI enables your physician to view inside your body without the use of harmful x-rays or surgical procedures.
What to Expect
There are no particular dietary requirements prior to your MRI exam, and you can continue to take your usual medications, unless your doctor instructs otherwise. An MRI can last up to an hour or more, but the procedure itself is painless. The MRI machine creates a substantial magnetic field around you, and radio waves are directed at your body. A powerful magnetic field coupled with radio frequency waves construct computer images that are later reviewed by a radiologist.
A two-way intercom system enables communication between you and the technologist during the scan at all times. You will also be provided with an alarm button to signal the technologist of any distress you may encounter throughout the process.
Closed or open scan
A closed MRI machine resembles a tube with both ends open. A movable table slides you into the opening of the tube. If you are concerned about claustrophobia, let your know doctor before arriving for the scan. You may be prescribed a sedative to ease relaxation. An open MRI is similar but does not have a cover. In both instances, a technologist monitors you from another room. During an MRI scan, an interior component of an extensive magnet generates repeated thumping, tapping and a variety of other sounds. Earplugs or headphones may be offered to help obstruct the noise.
In some cases, gadolinium, a contrast dye, is injected through an intravenous (IV) line placed in a vein in your arm or hand after completing a scan series. It enhances the details and appearances of certain tissues to permit detection of specific conditions. The dye used for MRIs is safe and less likely to cause an allergic reaction than the material used for CT scans.
Pain and discomfort
Other than remaining very still for the IV injection and during the scan, there is no pain or discomfort associated with an MRI scan. You will lie on your back on a padded table with a bolster under your knees to alleviate pressure on your lower back. The scan is divided into sequences, so you will be able to stretch or move slightly between each sequence. However, you must remain completely still during each segment because movement can blur the resulting images. The only exception is during a functional MRI, when you are asked to perform a number of small tasks, including tapping your thumb against your fingers or answering simple questions. This helps the radiologist pinpoint the portions of your brain that control these actions.
When the MRI scan is complete, your IV will be removed. You can then change back into your clothes and return home.
Interpretation of the Results
A radiologist experienced in reading MRIs and other radiology results will analyze the images and send a signed report with explanations to your physician.