A magnetic resonance imaging (MRI) scan is an imaging test that creates detailed pictures of the body. It does this by using powerful magnets and radio waves. It does not use radiation, which is what is used for x-rays. An MRI scan can produce dozens, or even hundreds, of images of structures inside the body.
An MRI can be used to check:
- Structures of different parts of the body
- Blood flow
- For unusual growths, such as tumors
- For infection
Risks and/or side effects of MRI may include:
- Reactions to the medicine used to help the child relax or sleep. These reactions may include headaches, shivering, and vomiting.
- An allergic reaction to the dye used for the test, which may cause itching, a skin rash, or wheezing.
- Rarely, kidney damage from the dye.
There are no known side effects from the magnetic fields or radio waves used during an MRI.
MRIs can help a doctor get a clear view of structures inside the body, which makes it easier to diagnose certain health conditions.
Your child may have to prepare for an MRI by not eating or drinking anything for 4 to 6 hours beforehand. Tell your doctor if your child is afraid of close spaces. Your child may be given medicine to help them feel sleepy and less nervous.
Before the scan, be sure to tell your child’s doctor if your child has:
- Inner ear (cochlear) implants
- An insulin pump
- Artificial heart valves
- A heart defibrillator or pacemaker
- Any metal objects inside the body
- Kidney disease or dialysis
For safety, since the MRI contains powerful magnets, metal objects are not allowed in the room. Metal objects include:
- Jewelry and watches
- Pins, hairpins, and metal zippers
- Pens and pocketknives
- Eyeglasses and hearing aids
- Some dental devices like retainers
Your child may be asked to wear a hospital gown or clothing without any metal, such as sweatpants and a t-shirt. Your child will lie on a narrow table, which slides into a tunnel-shaped machine that takes the images. The scan usually takes about 30 to 60 minutes to complete, but it can take longer.
Some types of exams require a special dye to be given through a small tube—called an intravenous (IV) line—inserted into your child’s vein in the hand or arm. The dye helps the doctor see certain areas more clearly.
During the MRI, the person who operates the machine will watch your child from outside the room. Let your child know that you’ll be nearby during the scan. If your child does not take medicine to fall asleep during the MRI, they will be given a call button to push if they need anything.
The MRI machine makes loud knocking or banging sounds when it is being adjusted. Your child will wear headphones to protect their ears and to hear instructions. Music may be played in the headphones when instructions are not being given.
Once the MRI begins, your child must remain very still or the images may be fuzzy. At times, your child will be asked to hold their breath for a few seconds. If your child cannot remain still for the MRI, they will be given medicine to help them sleep or relax.
When you are given the results depends on when (time of day or day of week) and where (large hospital or small hospital) the MRI is done. After an MRI, a specialist (radiologist) will usually review the images within 24 hours. They will report their findings to your doctor, who will contact you about the results.
Depending on the MRI results, additional tests or medical procedures may be recommended to get more health information.
If your child did not receive medicine to sleep or relax, they should be able to return to their normal activities right after the MRI. If your child received medicine during the scan, they may feel sleepy or tired for several hours afterward.