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    Magnetic Resonance Imaging (MRI) of the Head

    How It Feels

    You will not have pain from the magnetic field or radio waves used for the MRI test. The table you lie on may feel hard and the room may be cool. 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 and flushing as it is put into your IV.

    In rare cases, you may feel:

    Risks

    There are no known harmful effects from the strong magnetic field used for MRI. But the magnet is very powerful. The magnet may affect pacemakers, implantable cardioverter-defibrillators (ICDs), artificial limbs, and other medical devices that contain iron. The magnet will stop a watch that is close to the magnet.

    Metal pieces in the eyes can damage the retina. If you might have metal pieces in your eye, an X-ray of the eyes may be done before the MRI. If metal is found, the MRI will not be done.

    Iron pigments in tattoos or tattooed eyeliner can cause skin or eye irritation.

    An MRI can cause a burn with some medicine patches. Be sure to tell your doctor if you are wearing a patch.

    There is a small chance of an allergic reaction if contrast material is used during the MRI. But most reactions are mild and can be treated with medicine. Contrast material that contains gadolinium may cause a serious problem (called nephrogenic systemic fibrosis) in people with kidney failure. If you have decreased kidney function or serious kidney disease, tell your doctor before having an MRI scan.

    There also is a slight risk of an infection at the IV site if contrast material was used.

    Results

    Magnetic resonance imaging (MRI) is a test that uses a magnetic field and pulses of radio wave energy to take pictures of the head.

    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.

    Magnetic resonance imaging (MRI) of the head

    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.

    WebMD Medical Reference from Healthwise

    Last Updated: September 09, 2014
    This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.

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