What is a Cardiac MRI Scan?
MRI stands for magnetic resonance imaging. An MRI machine uses a powerful magnet, radio waves and a computer to get images (pictures) of just about any body part, including the heart. MRI studies do not use radiation.
Cardiac MRIs are done on MRI machines with special software and cardiac-specific equipment. Four of our MRI machines are equipped for cardiac studies. Cardiac studies can be done only at our Burnet Campus.
A parent or legal guardian needs to be present to sign a consent form to treat the patient. This is signed when the patient is registered.
Reasons for a Cardiac MRI
Cardiac MRIs are usually done to evaluate the hearts of patients with very specific conditions. They are most often done on teenagers and young adults with previously identified congenital heart disease.
A cardiac MRI takes very clear pictures of the heart and blood vessels in the chest. MRI can be used regardless of the patient's size. A larger-limit the quality of other types of imaging studies, such as ultrasound / echocardiography. Also, a cardiac MRI is able to give details and measurements of certain heart parameters.
Details of Cardiac MRI Procedure
Who Performs Cardiac MRI?
The cardiac MRI test is done by a trained MRI technologist, with help from a pediatric MRI radiologist and a pediatric MRI cardiologist. The input of all of these people are needed to get the most complete cardiac study.
Interpreting Results
The study will be interpreted by both a pediatric MRI cardiologist and pediatric MRI radiologist. The final report, including numerical analysis and movie clips, will be available to your child's pediatric cardiologist within a few days.
Sedation
Most patients do not need sedation. Some young adult patients do have claustrophobia and difficulty lying in the magnet for a long time. For these patients, it is best to talk about anxiety relief with the ordering doctor before the appointment.
Breathing instructions will be given during the exam. It is best for the patient to be able to hold their breath when coached. The scan can be completed without breath-holds. As long as the patient can stay still and breathe comfortably, children can generally tolerate a cardiac MRI scan by watching a movie (on specially equipped virtual reality goggles) or listening to music. Anesthesia is usually only needed for children less than 6 years old (depending on the maturity level of the child).
When general anesthesia is needed, the Department of Anesthesiology runs the sedation, under the guidance of an attending anesthesiologist.
My Child Has Had Metal Clips / Implants Placed. Can They Still Have a Cardiac MRI?
Metal clips / implants will not usually affect the MRI. The only permanent, implanted devices absolutely not allowed in the MRI scanner are implanted defibrillators, since the powerful MRI magnet can theoretically disrupt the defibrillator function. The magnet does not disrupt function of other metal devices, such as implanted artificial heart valves, metal sternal wire, braces on the teeth, clips, or other devices. Certain selected patients with pacemakers can now also safely undergo MRI studies. This is reserved for very special circumstances. It needs a lot of planning and additional staff.
Patients will be asked to change into a hospital gown to avoid any risk of metal entering the scanner. If your child has had any metal implanted surgical devices in their chest, the devices may block areas of the heart and affect how useful the scan can be. Although this does not always make the procedure unsafe, it may make the results hard to read. In patients with several metal devices and / or coils in the chest, a chest X-ray may be done before the MRI so that the MRI radiologist and cardiologist can make sure there will not be too much interference.
Before the Cardiac MRI Scan
Before coming to the hospital or MRI facility, talk to your child about the scan. Depending on your child's reason for the exam, an IV may be needed for the MRI. If an IV is needed, topical anesthetic can be applied to your child shortly after check-in. The day of the exam, technologists will further explain the scan to your child and answer any questions.
You should get a phone call to confirm your appointment 24 to 48 hours before the MRI exam. We prepare all patients with specific eating and drinking instructions in case an IV is needed during the test. You will also be told to arrive 60 minutes before your scheduled scan to allow time for registration, removal of all jewelry and metal, and IV placement if needed.
The MRI machine is a large magnet. Remove all metal hair barrettes or rubber bands and earrings. Check any toys or stuffed animals for metal parts before bringing them to the MRI area.
Children are encouraged to bring music or a video to watch during the MRI scan.
During the Cardiac MRI Scan
The MRI machine is a large magnet that is in the shape of a tunnel. Whatever body part that is being scanned needs to be in the center of the tunnel.
While your child is lying on a table in the middle of the tunnel, nothing will touch or hurt them as the pictures are being taken. When we start to take pictures, loud knocking or banging noises will be heard. Whenever your child hears the loud noise, the machine is taking pictures. This is when they will need to hold perfectly still. To protect the child's hearing, earplugs or special headphones will be given to listen to music or a video.
The entire MRI study can be as short as 30 minutes but sometimes can last for up to two hours. Your child has to hold perfectly still (like a statue) while pictures are being taken. Several series of pictures will be taken. Each series will last between 30 seconds to seven minutes each. The technologist will talk to your child between each set of pictures to ensure that they are OK.
Parents are welcome to come with their child into the scan room, as long as you are not pregnant and all jewelry and metal are removed. Parents will be given earplugs during the scan.
Sometimes an IV is also used to give a small amount of contrast material during the test. This is a clear fluid that shows up on the pictures. The IV will stay in place until the scan is completed. If your child is unable to hold still for the pictures and they were scheduled for an MRI without sedation, you will most likely need to reschedule your appointment with sedation / anesthesia and return at a different date.
After the Cardiac MRI Scan
When the MRI pictures are complete, your child will lie on the table a few moments longer while a radiologist checks to make sure there are enough pictures. Sometimes a set of pictures will need to be repeated (this takes five to 10 minutes).
Once the doctor checks the pictures and confirms that the scan is complete, the IV will be removed and the patient and family may leave.
