Your Child's Heart MRI or CT Scan

Boy lying on back on scanner table. Healthcare provider is preparing table to go into ring-shaped opening.

Radiographic studies, such as cardiac MRI and cardiac CT scan, are called imaging tests. They allow the healthcare provider to check for problems in the heart. The tests are painless and noninvasive. Your child’s healthcare provider will discuss with you why your child needs one or both of these tests. Most MRI tests take 30 to 60 minutes. Depending on the type of MRI your child is having, the test may take longer. Give yourself extra time to check your child in. 

What are cardiac MRI and CT scan?

Both cardiac MRI and cardiac CT scan are used to take images of the heart:

  • Cardiac MRI. This uses strong magnets and radio waves. A cardiac MRI scan can show problems with heart structure, abnormal blood flow, or tissue damage.

  • Cardiac CT scan. This uses X-rays and computer processing technology. A cardiac CT scan can show problems with heart structure, especially if there is damage to blood vessels.

Before the MRI or CT scan

You may need to do the following before your child’s cardiac MRI or CT scan:

  • Follow any directions your child is given for taking medicines and for not eating or drinking before the test.

  • Your child can follow his or her normal daily routine unless the healthcare provider tells you otherwise.

  • Make sure your child removes any makeup. Makeup may contain some metal.

  • Remove ear (cochlear) implants.

  • Make a list of all known implanted devices and any metal in your child's body. These include shrapnel or bullet fragments. Discuss these with your child's healthcare provider and the MRI technologist. If there is any uncertainty, an X-ray may be taken of the involved body part to be sure.  

  • Remove any metal objects, including watches, eyeglasses, hearing aids, jewelry, belts, or clothing with zippers, from your child. These things may interfere with the MRI scanner’s magnetic field. Dental braces and fillings aren’t a problem. But in many cases, MRI scans shouldn’t be done on children who have metal implants.  

MRI uses strong magnets. Metal is affected by magnets and can distort the image. The magnet used in MRI can cause metal objects in your child’s body to move. If your child has a metal implant, he or she may not be able to have an MRI unless the implant is certified as MRI safe. People with these implants should not have an MRI:

  • Certain clips used for brain aneurysms

  • Certain metal coils put in blood vessels

  • Ear (cochlear) implants

  • Most defibrillators

  • Most pacemakers

Tell your child’s healthcare provider and the technologist doing the scan if your child:

  • Has a bullet or other metal in his or her body

  • Has a pacemaker, surgical clips, metal plate or pins, an artificial joint, staples or screws, ear (cochlear) implants, or other implants

  • Has braces; in most instances, braces will not prevent you from having an MRI, but they can impact the quality of facial or head images 

  • Has had previous surgery

  • Has implanted nerve stimulators or drug-infusion ports

  • Has metal splinters in his or her body

  • Has tattoos or body piercings; some tattoo inks contain metal that can become hot during imaging

  • Wears a medicated adhesive patch

Follow all other instructions given by your child’s healthcare provider.

Also tell the technologist or healthcare provider if your child:

  • Gets nervous or scared in small, enclosed spaces (claustrophobic)

  • Has any metal in his or her body, including implants like pacemakers

  • Has allergies to X-ray dye (contrast medium), iodine, shellfish, or any medicines

  • Has any serious health problems. This includes kidney disease or a liver transplant. Your child may not be able to have the contrast material used for MRI.

  • Is pregnant or breastfeeding 

During the scan

The scan is done by a technologist or radiologist. A radiologist is a doctor trained to diagnose and treat problems with imaging technology. The scan can also be done by a cardiologist with special training in radiology. A cardiologist is a doctor trained to diagnose and treat heart problems. The scan can take place in either a hospital or outpatient imaging center. A cardiac MRI scan lasts about 60 to 90 minutes. A cardiac CT scan lasts about 30 minutes:

  • You can stay with your child in the testing room until the scanning begins.

  • Your child lies on a table that slides into the scanner.

  • Your child must stay still during the scan. Movement affects the quality of the results and can even need a repeat scan. To help keep your child still, restraints may be used. Your child may also be given a sedative (medicine that makes your child relax or sleep). This is done by mouth or through an IV line. Or your child is given anesthesia (medicine that makes your child sleep and not feel pain). This is done by facemask or IV. A trained nurse or another healthcare provider (anesthesiologist) is in charge of this process.

  • Contrast dye may be used to improve image results. Your child is given contrast dye by mouth or an IV line.

  • A coil may be placed over the heart during a cardiac MRI scan. The coil sends and receives radio waves and helps improve image results.

  • Small, EKG stick-on type patch leads may be attached to the chest. 

  • The technologist is nearby and views your child through a window at all times.

  • If awake, your child can speak to and hear the technologist through a speaker inside the scanner.

  • During a cardiac MRI scan, your child will get earplugs to block out the noise from the scanner.

  • During a cardiac CT scan, older children may be asked to hold their breath at certain points to improve image results.

After the scan

What to expect after the scan:

  • If a sedative or anesthesia was given, your child may be taken to a recovery room. It may take 1 to 2 hours for any medicines to wear off.

  • Unless told not to, your child can return to a normal routine and diet right away.

  • Any contrast dye your child is given should pass through the body in about 24 hours. The healthcare provider may tell you that your child should drink extra water or other fluids during this time.

  • The images are reviewed by a radiologist and cardiologist. The cardiologist will follow up with you with complete results.

Risks and possible complications of cardiac MRI and CT scan

Risks and possible complications include: 

  • Allergic reaction to contrast dye, such as hives, itching, or wheezing

  • Kidney damage from IV contrast dye used in CT scan (rarely)

  • Nephrogenic systemic fibrosis, an illness that has been linked to MRI IV contrast material (extremely rare)

  • Problems with undetected metal implants or foreign bodies (only with MRI)

  • Radiation exposure from X-rays (only with CT scan)

  • Reaction to sedative or anesthesia, such as headaches, shivering, and vomiting

How to help your child prepare

You can help your child by preparing in advance. How you do this depends on your child’s needs:

  • Explain the test to your child in brief and simple terms. Younger children have shorter attention spans, so do this shortly before the test. Older children can be given more time to understand the test in advance.

  • Make sure your child understands which body part(s) will be involved in the test.

  • As best you can, describe how the test will feel. An IV may be inserted into the arm or hand to give medicines or contrast dye. This may cause a brief sting. Your child won’t feel any discomfort once the medicines take effect. If awake, your child may become uncomfortable from lying still.

  • Allow your child to ask questions and answer those questions truthfully. Your child may feel nervous or afraid. He or she may even cry. Let your child know that you’ll be nearby during the test.

  • Many hospitals have a child life specialist. This person is specially trained to help children understand what to expect during their time in the hospital. Books, videos, dolls, and toys may be used to help explain the procedure to your child. Be sure to ask your child’s healthcare provider about the resources available at your hospital.