Magnetic resonance imaging is a noninvasive, painless, medical imaging test. MRI scanners use a high-powered magnet, radio waves and computers to generate detailed cross-sectional images of the inside of your body. These images are in much greater detail than what can be obtained using CT technology.
The use of MRI technology has skyrocketed during the past few years and is credited with helping to detect many conditions at an earlier stage. These detailed scans are also useful to your doctors as they plan a treatment course for you.
MRI is useful for obtaining images of the brain and spine, as well as the soft tissues of joints and the interior structure of bones.
MRI is often used to scan:
- Hands and wrists
- Ankles and feet
What to expect when you have an MRI
What to do before the test
- Unless you are told otherwise, you may follow your regular daily eating and drinking routine, taking medicines as usual.
- If your doctor is using a contrast substance or "dye," to watch the path of blood flow or other movement through your body, the technologist will ask if you have allergies or any kind of serious health problems.
- Please leave jewelry and other accessories at home as metals interfere with the MRI test.
- You should tell the technologist if you have medical or electronic devices in your body because they may interfere with the exam or may pose a risk to you.
- Ask the testing center in advance if a family member or friend is allowed in the room with you.
- If you are concerned you may get anxious or have claustrophobia during the test, ask your doctor in advance of the exam for a sedative.
- Wear loose fitting clothing that has no metal fasteners. You may be asked to wear a gown during the exam.
The MRI machine
The MRI machine is a large cylinder-shaped tube surrounded by a circular magnet. It has a hole in the middle where a moveable table slides in and out. When you lie on the table and it slides in and out, this space can sometimes feel very narrow. Some MRI units are designed so that the magnet does not completely surround you and others are open on all sides.
The MRI technologist will operate the MRI machine and monitor your examination from a separate room with windows. During the entire test, you will always be able to talk back and forth with the technologist.
Here is what you will experience
- The technologist will position you on the moveable examination table.
- Transmitters may be placed around the area of the body your doctor wants to study.
- Bolsters or straps may be used to help keep you keep completely still - remember, the better the image the more accurate the diagnosis.
- You will slowly be moved into the MRI unit.
- The MRI scanner makes loud thumping noises while it is producing images. It records images for a few seconds or a few minutes at a time. It is important that you are completely still while the images are being taken.
- The scanner is air-conditioned and well lit. You may request earplugs or you may ask that music be piped in during your test.
After an initial series of scans are performed, if a contrast substance or dye is used, it will be injected into an intravenous line, or IV, that was put in before the exam. You may feel a cool flush from the IV for a few minutes. Following the dye injection into the IV, an additional series of images will be taken.
Following the exam
You may resume your usual activities and normal diet immediately after the 45- to 60-minute exam. Your primary care or referring physician will receive a copy of the images and test report and will discuss the results with you.