Magnetic resonance imaging (MRI) uses a large magnet, radiofrequencies, and a computer to produce detailed pictures of organs and structures within the body. It is used to diagnose medical problems.
The MRI machine is a large, tube-shaped machine that creates a strong magnetic field around the person being examined. Some look like narrow tunnels, while others are more open. This magnetic field, along with a radiofrequency, briefly redirects the hydrogen atoms' natural alignment in the body. Computers are then used to form two-dimensional (2D) images of a body structure or organ based on the activity of the hydrogen atoms. Cross-sectional views can be done to show more details. MRI does not use ionizing radiation, like X-rays or computed tomography (CT scans).
An MRI may be used to examine bones, joints, and soft tissues such as cartilage, muscles, and tendons for things like:
There may be other reasons for your healthcare provider to recommend an MRI of the bones, joints, or soft tissue.
There is no risk of exposure to radiation during an MRI procedure.
Due to the use of the strong magnet, MRI can’t be used for people with the following:
If you are pregnant or think you may be, tell your healthcare provider. In general, there is no known risk of MRI in pregnancy. However, particularly in the first trimester, MRI should only be used to address very important problems or suspected abnormalities.
If contrast dye is used, there is a risk for allergic reaction to the dye. If you are allergic to or sensitive to medicines, contrast dye, or iodine, tell your healthcare providers.
MRI contrast may have an effect on other conditions such as allergies, asthma, anemia, low blood pressure, kidney disease, and sickle cell disease.
Nephrogenic systemic fibrosis (NSF) is a very rare but serious complication of MRI contrast use in people with kidney disease or kidney failure. If you have a history of kidney disease, kidney failure, kidney transplant, liver disease, or are on dialysis, be sure to tell the MRI technologist or radiologist before getting the contrast.
There may be other risks depending on your specific medical condition. Be sure to discuss any concerns with your healthcare provider before the procedure.
Your healthcare provider will explain the procedure to you and give you a chance to ask any questions.
If your MRI involves the use of contrast dye, you will be asked to sign a consent form that gives permission to do the procedure. Read the form carefully and ask questions if anything is not clear.
Generally, there is no special restriction on diet or activity prior to an MRI.
Before the MRI, it is extremely important that you inform the technologist if any of the following apply to you:
There is a possibility that you may get a sedative before the procedure, so you should plan to have someone drive you home afterward.
Based on your medical condition, your healthcare provider may request other specific preparation.
MRI may be done on an outpatient basis or as part of your stay in a hospital. Procedures may vary depending on your condition and your healthcare provider’s practices.
Generally, MRI of the bones, joints, or soft tissue follows this process:
While the MRI procedure itself causes no pain, having to lie still for the length of the procedure might cause some discomfort or pain, particularly if you’ve recently been injured or had surgery. The technologist will use all possible comfort measures and complete the procedure as quickly as possible to minimize any discomfort or pain.
On occasion, some people with metal fillings in their teeth may experience some slight tingling of the teeth during the procedure.
Move slowly when getting up from the scanner table to avoid any dizziness or lightheadedness from lying flat for the length of the procedure.
If any sedatives were used for the procedure, you may need to rest until the sedatives have worn off. You will also need someone to drive you home.
If contrast dye is used, you may be monitored for a period for any side effects or reactions to the contrast dye, such as itching, swelling, rash, or difficulty breathing.
If you notice any pain, redness, and/or swelling at the IV site after you go home, you should tell your healthcare provider as this could be a sign of infection or other type of reaction.
Otherwise, there is no special type of care required after a MRI scan of the bones, joints, and soft tissues. You may go back to your usual diet and activities, unless your healthcare provider tells you differently.
Your healthcare provider may give you other instructions after the procedure, depending on your particular situation.
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