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Our Health Library information does not replace the advice of a doctor. Please be advised that this information is made available to assist our patients to learn more about their health. Our providers may not see and/or treat all topics found herein. Magnetic resonance imaging (MRI) is a test that uses a magnetic field and pulses of radio wave energy to take pictures of the head. In many cases, MRI gives information that can't be seen on an X-ray, ultrasound, or computed tomography (CT) scan. For an MRI of the head, you lie with your head inside a special machine (scanner) that has a strong magnet. The MRI can show tissue damage or disease, such as infection or inflammation, or a tumor, stroke, or seizure. Information from an MRI can be saved and stored on a computer for more study. Photographs or films of certain views can also be made. In some cases, a dye (contrast material) may be used during the MRI to show pictures of structures more clearly. The dye may help show blood flow, look for some types of tumors, and show areas of inflammation. An MRI of the head may be used to look for the cause of headaches. Magnetic resonance imaging (MRI) of the head is done to: In general, there's nothing you have to do before this test, unless your doctor tells you to. Tell your doctor if you get nervous in tight spaces. You may get a medicine to help you relax. If you think you'll get this medicine, be sure you have someone to take you home. The test usually takes 30 to 60 minutes but can take as long as 2 hours. You won't have pain from the magnetic field or radio waves used for the MRI test. But you may be tired or sore from lying in one position for a long time. If a contrast material is used, you may feel some coolness when it is put into your I.V. In rare cases, you may feel: There are no known harmful effects from the strong magnetic field used for an MRI. But the magnet is very powerful. It may affect any metal implants or other medical devices you have. Contrast material that contains gadolinium may be used in this test. But for most people, the benefit of its use in this test outweighs the risk. Be sure to tell your doctor if you have kidney problems or are pregnant. There is a slight chance of an allergic reaction if contrast material is used during the test. But most reactions are mild and can be treated using medicine. If you breastfeed and are concerned about whether the contrast material used in this test is safe, talk to your doctor. Most experts believe that very little dye passes into breast milk and even less is passed on to the baby. But if you are concerned, you can stop breastfeeding for up to 24 hours after the test. During this time, you can give your baby breast milk that you stored before the test. Don't use the breast milk you pump in the 24 hours after the test. Throw it out. The radiologist may tell you some of the results of the MRI right after the test. Full results are sent to your doctor or specialist in 1 to 2 days. Normal: All structures of the head—the brain, its vessels, spaces, nerves, and surrounding structures—are normal. No abnormal growths, such as tumors, in or around the brain are present. No bleeding, abnormal blood vessels (AV malformations), abnormal pockets of fluid, blockage in the flow of blood, or bulges in the blood vessels (aneurysm) are present. No signs of infection or inflammatory disease, such as encephalitis or meningitis, are present. Abnormal: Tumors in the brain or in areas outside the brain, such as an acoustic neuroma, are present. Bleeding or swelling (edema) in or around the brain is present. Areas of infection or inflammatory disease, such as encephalitis or meningitis, are present. Abnormal areas in the brain may mean that certain diseases, such as Huntington's disease, multiple sclerosis, Parkinson's disease, or Alzheimer's disease, are present. Bulges or weak areas (aneurysms) or abnormal blood vessels (such as an AV malformation) are present. Current as of: July 26, 2023 Author: Healthwise Staff Current as of: July 26, 2023 Author: Healthwise Staff Clinical Review Board This information does not replace the advice of a doctor. Healthwise, Incorporated disclaims any warranty or liability for your use of this information. Your use of this information means that you agree to the Terms of Use and Privacy Policy. Learn how we develop our content. To learn more about Healthwise, visit Healthwise.org. © 1995-2024 Healthwise, Incorporated. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.Magnetic Resonance Imaging (MRI) of the Head
Test Overview
Why It Is Done
How To Prepare
How It Is Done
How long the test takes
How It Feels
Risks
Risks from contrast material
Results
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Clinical Review Board
All Healthwise education is reviewed by a team that includes physicians, nurses, advanced practitioners, registered dieticians, and other healthcare professionals.
All Healthwise education is reviewed by a team that includes physicians, nurses, advanced practitioners, registered dieticians, and other healthcare professionals.