MRIs are used to provide a detailed snapshot of what’s happening inside of your body. Magnetic resonance imaging uses a strong magnetic field, radio waves and a computer to monitor, treat and diagnose various parts of the body. Pregnant women commonly use MRIs to track the progress their unborn baby. You also might see professional athletes using this post-injury to see the status of the ailments doctors can’t see with a regular x-ray.
Because radiation is not used, there is no risk of exposure to radiation during an MRI procedure. However, due to the use of the strong magnet, MRI cannot be performed on patients with:
- Implanted pacemakers
- Intracranial aneurysm clips
- Cochlear implants
- Certain prosthetic devices
- Implanted drug infusion pumps
- Neurostimulators
- Bone-growth stimulators
- Certain intrauterine contraceptive devices; or
- Any other type of iron-based metal implants.
If contrast dye is used, there is a risk for allergic reaction to the dye. Patients who are allergic to or sensitive to medications, contrast dye, iodine, or shellfish should notify the radiologist or technologist. MRI contrast may also have an effect on other conditions such as allergies, asthma, anemia, hypotension (low blood pressure), and sickle cell disease.
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Like surgery, there are some pre-planning measures to take before going in for an MRI to ensure the highest quality experience. Here’s your complete FAQ to preparing for your MRI.
When should I arrive?
Arrive 30 minutes prior to your exam and check in with the receptionist. The reception will have you complete an MRI screening form. If you’re required to change clothes, they’ll give you a locker to store your belongings in and give you a hospital gown to change into. A technologist will verify your screening form in consultation with the radiologist.
What is the experience like?
The procedure usually lasts for 45 minutes to an hour depending on the body part being scanned. You’ll be lying still, but don’t worry it won’t be too uncomfortable. Depending on which body part is being scanned you might be told to hold your breath for 30 seconds. The unit is well lit and there is a fan going for your comfort. While the imaging is going on you’ll hear some loud noises, so your doctor will give you some earplugs to drown out the sound. The technologist taking care of you during this time will also provide you with an alarm button to alert them if you’re experiencing any pain or discomfort during this time.
What should I wear?
Doctors will inform you prior the exam whether or not you can wear your regular clothes to the MRI. If they allow you to wear regular clothes to the exam, they’ll more than likely tell you to wear loose-fitting clothes with no metal fasteners. Otherwise they’ll provide you with a hospital gown.
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Can I eat and/or drink before the exam?
Depending on the exam you get, your doctor may or may not tell you to eat or drink prior to the exam. Each exam is different and requires different preparation. Unless told otherwise, follow your regular daily eating schedule.
What does the doctor need to know about me before the exam?
It’s important to let your doctor know of any allergies that you have. Some MRI examinations require the usage of injections that may contain substances that cause adverse reactions to pre-existing allergies. Doctors normally prescribe pre-medication to their patients to counteract these adverse reactions. Some MRI examinations require the use of MRI contrasts. These MRI contrasts are dye-like injections given to patients to make certain diseases, tissues and abnormalities appear even better while scanning your body. This helps doctors detect those hard to find issues in your body by making them stand out for the MRI scan. These contrasts are given intravenously before the MRI starts.
Please let your radiologist know if you’ve had any recent surgeries. This is a safeguard for your health because the MRI can cause a great deal of stress on certain body parts if they aren’t functioning adequately.
Pregnant women and women potentially expecting should let their doctor or radiologist know of their status. Although MRI’s have been used since the 80’s without any damaging effects to women and their unborn child, its not recommended for women in their first trimester. The strong magnetic field combined with the fragile state of the unborn child poses a great risk to the success of the pregnancy.
Inform your doctor if you’re suffering from claustrophobia or anxiety. To give you a snapshot of what the structure looks like; the MRI unit is a large cylinder shaped tube surrounded by a big magnet. In order to have the MRI performed you’ll have to lie on a moveable examination table that slides into a tightly enclosed space inside of the MRI unit. Doctors normally prescribe sedatives or other medicines to ease and calm patients who suffer from either condition.
What shouldn't I bring to the exam?
Jewelry, metal and electronic items should be left at home if possible. They can cause great interference with the magnetic field of the MRI unit. Other items to leave at home or in the waiting room: watches, credit cards, hearing aids, hairpins, metal zippers, removable dental appliances, pens, pocket knives, eye glasses and body piercings.
If you have any of the following metal implants inform your doctor: cochlear(ear) implants, brain clips, cardiac defribillators, pacemakers and metal coils place in blood vessels. Many of these implants and devices come with a pamphlet explaining the MRI risks. Certain implanted devices are to safe use after placement(normally six weeks but ask your doctor). Devices such as: artificial heart valves, implanted drug infusion ports, artificial limbs, metallic joint prostheses, implanted nerve stimulators, metal pins, screws and surgical staples to name a few.
