Published: May 16, 2007
Updated: Aug. 22, 2011
What is an MRI?
Magnetic resonance imaging (MRI) is a special test that produces very clear, detailed
pictures of the organs and structures in your body. The test uses a powerful magnetic field, radio waves, and a computer to create images in cross-section.
What information will it give my doctors?
While an x-ray is very good at showing bones, an MRI lets your doctor see structures made of soft tissue such as ligaments and cartilage and organs such as your eyes, brain, and heart.
Doctors use MRIs to see problems in the brain and spinal cord and to see the size and location of tumors. Injuries show up well on an MRI. For example, an MRI may show whether you have torn ligaments or torn cartilage in your knee and help your doctor decide whether you need surgery. It is also useful for injuries involving the shoulder, back, or neck.
What should my doctor know before I have this test done?
If you have any metal in your body (such as plates or screws from a previous surgery) tell your doctor. If you have a pacemaker you cannot have an MRI because the test may damage
it. If you have any metal fragments in your eyes you cannot have an MRI because the test
may injure your eyes.
If you get nervous when you are in small closed spaces, you should talk to your doctor about this before you have your MRI. He or she may be able to give you a medication that will help you feel less nervous.
Where is this test done?
Duke has three MRI facilities. One is located on the first floor of Duke University Hospital, in the Radiology Department. The second is located in the imaging facility on Herndon Road. The third is a unit located off Erwin Road, beside Lennox-Baker Children's Hospital. If your appointment is scheduled for one of the off-site facilities, you will be given a map or may call 919-684-7399 for directions.
How do I prepare for an MRI?
No special preparation is needed. You may eat normally and take any usual medications.
For the test, wear loose, comfortable clothing without metal fastenings such as zippers or clasps because metal will interfere with the test. You may be asked to change into a patient gown. Keep jewelry to a minimum as you will need to remove it for the MRI.
When you come for your study, you will be asked to remove personal items such as your watch, wallet, purse, car keys, etc. Secure lockers are provided for your belongings; you keep the key with you.
An adult friend or family member may go into the MRI room with you. They will need to secure personal belongings in a locker, as well.
What happens during the MRI?
You lie down on a cushioned bed that moves into a doughnut-shaped magnet that is open
on both ends. You will have to be very still during the procedure so the pictures will not be blurry. While the study in going on, you will be in constant voice communication with the technologist through an intercom system. The technologist will tell you when you may move and when you must be still.
An MRI usually takes between 30 and 60 minutes for each body part being imaged. You will hear loud knocking and a whirring sound while the pictures are being taken. You will wear earplugs or music will be provided so that the noise doesn't sound so loud.
In some cases, the radiologist may decide to use a enhancement (contrast) agent to make certain details more clear. This contrast material is a fluid that is injected into a vein (usually in your arm). Additional MRI images are taken after the injection. This contrast is not the same as that used in Radiology or the CT department. If contrast is needed in your study, that does not mean that your condition is serious or that anything is wrong with you. It simply means that additional information is needed to provide a more complete answer for your physician.
What happens after the MRI?
No special care is needed after an MRI. No aftereffects are expected.
Do I need to have someone drive me home afterward?
You will not need someone to drive you home unless you have had medicine to help you relax.
What are the risks of an MRI?
The MRI is a very safe procedure. The major risks associated with an MRI relate to the presence of foreign objects in or on the body, such as pacemakers, monitoring leads, or metal fragments. Take care in answering all questions on the pre-MRI questionnaire as thoroughly and accurately as you can. Ask the MRI staff for assistance if you are uncertain about how to answer any of the questions.
How will I get the results of the MRI?
The MRI radiologist will be reviewing the images during your scan to ensure that there are clear pictures to answer the question your doctor has. After all the images are transferred to film, a group of MRI radiologists will discuss your images and interpret them. The final written results will be sent to your physician, usually within three working days. On occasion, your physician will call us on the same day as the study for a verbal preliminary report. You will hear the results from your doctor or other health care provider.
This article is intended as a resource for patients receiving their cancer care at Duke University Hospital or Duke Clinic. It is not intended to substitute for medical advice from your health care team. If your doctor’s instructions differ from the information in this article, please talk with your doctor before making any changes.
Source: Duke Cancer Patient Education Program / Patient & Family Education Committee 8/00