Magnetic Resonance Imaging (MRI)
For an MRI, 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.
Guidelines about eating and drinking before an MRI exam vary with the specific exam and MRI facility. Unless you are told otherwise, you may follow your regular daily routine and take food and medications as usual.
Some MRI examinations may require the patient to receive an injection of contrast material into the bloodstream. The radiologist or technologist may ask if you have allergies of any kind, such as allergy to iodine or x-ray contrast material, drugs, food, the environment or asthma.
The contrast material most commonly used for an MRI exam, called gadolinium, does not contain iodine and is less likely to cause side effects or an allergic reaction.
The radiologist should also know if you have any serious health problems or if you have recently had surgery. Some conditions, such as severe kidney disease may prevent you from being given contrast material for an MRI. If there is a history of kidney disease, it may be necessary to perform a blood test to determine whether the kidneys are functioning adequately.
Women should always inform their physician or technologist if there is any possibility that they are pregnant. MRI has been used for scanning patients since the 1980s with no reports of any ill effects on pregnant women or their babies. However, because the baby will be in a strong magnetic field, pregnant women should not have this exam unless the potential benefit from the MRI exam is assumed to outweigh the potential risks.
Pregnant women should not receive injections of contrast material.
Jewelry and other accessories should be left at home if possible, or removed prior to the MRI scan. Metal and electronic objects are not allowed in the exam as they interfere with the magnetic field of the MRI unit. 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
In most cases, an MRI exam is safe for patients with metal implants, with a few exceptions. People with the following implants that are not pre-approved by the radiologists my not be scanned and should not enter the MRI scanning area unless explicitly instructed to do so by the radiologist or technologist who is aware of the presence of any of the following:
- internal (implanted) defibrillator or pacemaker
- cochlear (ear) implant
- some types of clips used on brain aneurysms
- some types of metal coils placed within blood vessels
You should tell the technologist if you have medical or electronic devices in your body, because they may interfere with the exam or potentially pose a risk, depending on their nature and the strength of the MRI magnet. Examples include but are not limited to:
- artificial heart valves
- implanted drug infusion ports
- implanted electronic device, including a cardiac pacemaker
- artificial limbs or metallic joint prostheses
- implanted nerve stimulators
- metal pins, screws, plates, stents or surgical staples
In general, metal objects used in orthopedic surgery typically pose no risk during MRI. However, a recently placed artificial joint may require the use of another imaging procedure. If there is any question of their presence, an x-ray may be taken to detect the presence of and identify any metal objects.
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 technologist or radiologist of any shrapnel, bullets or other pieces of metal which may be present in your body due to accidents.
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 radiologist should be aware of them.
Please consult with CIS if your infant or young child will be having an MRI exam. You will be given special instructions on how to prepare your child.
View the video from our CIS affiliate, Diagnostic Imaging Services, to get an overview of what to expect with any MRI exam. While the video pertains specifically to our high field open MRI, the processes and information provided apply to all studies performed by Capitol Imaging Services on our MRI systems.
Magnetic Resonance Angiography (MRA)
MRA is a non-invasive technique on the MRI scanner to image blood vessels of any body part, most commonly those in the head and neck. MRA is an alternative to conventional angiography, which requires the insertion of needles and catheters into the blood vessels with the use of x-ray.
For the following MRI or MRA examinations, please do not wear eye makeup:
- MRI – Brain/Neck
- MRI – Facial
- MRI – Internal Auditory Canals (IAC’s)
- MRI – Parotid gland
- MRI – Pituitary gland
- MRA – Circle of willis
Additional special instructions for MRI and MRA include:
MRI – MRCP (Magnetic Resonance Cholangiopancreatography)
- Please fast six hours prior to your examination
MRA – Head and/or Neck
- Please bring previous films (MRI or CT) for your examination, if done at an outside facility
MRI – Prostate gland
- Do not have anything containing caffeine for 24 hours before your exam
- Do not consume any alcoholic beverages for 24 hours before your exam
- Please abstain from sex 24 hours before your exam
- There should be no ejaculation 24 hours before your exam
- You need to fast for 4 to 6 hours before your exam
- Your exam should be done at least 6 weeks after your last prostate biopsy
- Please ask your doctor (or bring with you) to send copies of your previous biopsy and PSA results in advance of your visit; this information is required for this exam
- Please ask your doctor (or bring with you) results of any and all lab work that you have had done