CHS

How should I prepare for this test?

​You may be asked to wear a gown during the exam or you may be allowed to wear your own clothing if it is loose-fitting and has no metal fasteners.

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Guidelines about eating and drinking before an MRI exam vary with the specific exam and also with the imaging facility. Unless you are told otherwise, you may follow your regular daily routine and take food and medications as usual.

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Some MRI examinations may require you to receive an injection of contrast material into the bloodstream. The  technician or a nurse may ask if you have allergies of any kind, such as an allergy to iodine or x-ray contrast material, drugs, food, or the environment, or if you have asthma. 

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You should also let the technician know if you have any serious health problems, or if you have had any recent surgeries. Some conditions, such as severe kidney disease, may prevent you from being given  contrast for an MRI. If you have a history of kidney disease or liver transplant, it will be necessary to perform a blood test to determine whether the kidneys are functioning adequately.

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Women should always inform their physician or technologist if there is any possibility that they are pregnant.

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If you have claustrophobia (fear of enclosed spaces) or anxiety, you may want to ask your physician for a prescription for a mild sedative prior to your scheduled examination.

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Jewelry and other accessories should be left at home if possible, or removed prior to the MRI scan. Because they can interfere with the magnetic field of the MRI unit, metal and electronic items are not allowed in the exam room. These items include:

• jewelry, watches, credit cards and hearing aids, all of which can be damaged

• pins, hairpins, metal zippers and similar metallic items, which can distort MRI images

• removable dental work

• pens, pocket knives and eyeglasses

• body piercings

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In most cases, an MRI exam is safe for patients with metal implants, except for a few types. People with the following implants cannot be scanned and should not enter the MRI scanning area:

• cochlear (ear) implant

• some types of clips used for brain aneurysms

• some types of metal coils placed within blood vessels

• nearly all cardiac defibrillators and pacemakers

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You should tell the technician if you have medical or electronic devices in your body. These objects may interfere with the exam or potentially pose a risk, depending on their nature and the strength of the MRI magnet. Many implanted devices will have a pamphlet explaining the MRI risks for that particular device. If you have the pamphlet, it is useful to bring that to the attention of the technician or scheduler before the exam. Some implanted devices require a short period of time after placement (usually six weeks) before being safe for MRI examinations. Examples include but are not limited to:

• artificial heart valves

• implanted drug infusion ports

• artificial limbs or metallic joint prostheses

• implanted nerve stimulators

• metal pins, screws, plates, stents or surgical staples

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In general, metal objects used in orthopedic surgery pose no risk during MRI. However, a recently placed artificial joint may require the use of another imaging procedure.

Patients who might have metal objects in certain parts of their bodies may also require an x-ray prior to an MRI. You should notify the technician of any shrapnel, bullets, or other pieces of metal which may be present in your body due to prior accidents. Foreign bodies near and especially lodged in the eyes are particularly important. Dyes used in tattoos may contain iron and could heat up during MRI, but this is rarely a problem. Tooth fillings and braces usually are not affected by the magnetic field, but they may distort images of the facial area or brain, so the technician should be aware of them.