An MRI is a non-invasive and painless procedure in which radio waves and powerful magnets linked to a computer are used to create remarkably clear and detailed pictures of internal organs and tissues without the use of radiation. Each MRI produces hundreds of pictures from side-to-side, top-to-bottom, and front-to-back. These pictures show the difference between normal and diseased tissue and enable doctors to determine what the inside of a particular structure looks like. This makes it very useful in diagnosing abnormalities. The technique has proven very valuable for the diagnosis of many conditions in all parts of the body including cancer, heart and vascular disease, stroke, breast disease, and joint and musculoskeletal disorders. When visualizing an MRI, it might be helpful to think of a loaf of bread and the many slices in it. An MRI takes a body part, slices it and takes hundreds of pictures of hundreds of different slices.
MRI provides an unparalleled view inside your body. It has become the preferred procedure for diagnosing a large number of potential problems in many different parts of the body. In the head, trauma to the brain can be seen as bleeding or swelling. Other abnormalities often found include brain aneurysms, stroke, tumors of the brain, as well as tumors or inflammation of the spine. Physicians use an MRI scan not only in defining anatomy but in evaluating the integrity of the spinal cord after trauma. It is also used when considering problems associated with the vertebrae or discs of the spine. An MRI scan can evaluate the structure of the heart and aorta. It provides valuable information on glands and organs within the abdomen as well as information about the structure of the joints, soft tissues and bones of the body.
MRI can easily be performed through clothing. However, certain types of metal in the area being scanned can cause significant errors, called artifacts, in the images. You will be asked to remove your jewelry, watch, hairpins, bobby pins, hearing aids, removable dental work and glasses. You hair should be free of hairspray or styling gel. You may be asked not to eat or drink anything prior to your exam depending on the procedure you are having performed.
The technologist will ask you questions before you have your procedure. It is very important for he or she to know if you have:
- Had any surgeries
- A pacemaker
- Aneurysm clips
- A history of working with metal
- An implanted drug infusion device
- A history of injury during military service (by bullet or shrapnel)
- Metallic plates, pins, screws or other implants (usually do not cause a problem if they have been in place more than 4 to 6 weeks)
- An IUD (Intrauterine Device)
- Tattoos or permanent makeup
- A trans-dermal patch, nicotine or hormone patch
- Had a previous MRI exam
Check with the technologist or radiologist if you have any questions or concerns about any implanted object or health condition that could impact your MRI.
If you think you might be pregnant, you should notify the technologist. Because of the nature of the machine and being placed into a confined space, some patients who undergo MRI feel claustrophobic. If you are extremely claustrophobic, check with your testing facility to see if administration of a sedative is an option. Only about 3% of all MRI patients suffer from extreme claustrophobia and may not tolerate an MRI in a traditional machine. If you feel you are in this category, you may have the option of an Open MRI where claustrophobia is lessened.
Your technologist has been specially trained. He or she will make sure you are comfortable during your MRI and will answer all of your questions regarding this test. After changing into a gown, the technologist will position you on a special sliding table that moves into the MRI machine during your exam. A special coil may be placed over the area to be examined to improve the quality of the images. You will be under constant observation and will be able to talk to the technologist at all times. Some facilities provide either ear plugs or headphones for you to listen to music during your exam.
An MRI exam is one of the easiest and most comfortable exams you can have. During the exam the technologist will talk to you as the scanner goes through a series of scanning sequences. You will hear noises while the machine is taking pictures ranging from a grating sound to a tapping sound as the scanner changes to different sequences. Your technologist will tell you before each set so you can be ready and relaxed. You will be asked not to move during the actual imaging process, but between sequences some movement is allowed. Generally you will only need to be completely still for a few seconds to a few minutes at a time.
For some MRI studies, a contrast agent (usually gadolinium) may be used to enhance the visibility of certain tissues or blood vessels. This will require an IV in your vein. The IV will contain a saline solution that will drip slowly to prevent clotting of the IV until the contrast material is injected about two-thirds of the way through your exam. This contrast agent does not contain iodine. The exam generally takes 30 to 45 minutes.
When the exam is over, you may be asked to wait until the images are reviewed to determine if more images are needed. If you were placed on any dietary restrictions, you may resume your normal diet following the exam.
Every year approximately 10 million patients undergo MRI procedures. MRI has been shown to be extremely safe as long as proper safety precautions are taken with regard to metal objects. In general, the MRI procedure produces no pain and causes no short or long-term damage of any kind. The fact that there is no radiation exposure also decreases the risk when having an MRI.
A radiologist, a physician experienced in MRI and other radiology examinations, will analyze the images and send a signed report with his or her interpretation to your healthcare provider. You will receive your MRI results from the healthcare provider that ordered the test. New technology also allows for distribution of reports over the internet at many facilities.