What is a Cardiac MRI Scan?
MRI stands for magnetic resonance imaging. An MR machine uses a powerful magnet, radio waves and a computer to acquire images (pictures) of just about any body part, including the heart. MRI studies use no radiation.
Cardiac MRIs are performed on MRI machines equipped 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 for evaluation of the heart of patients with very specific conditions. They are most commonly performed 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 (large size can often limit the quality of other types of imaging studies, such as ultrasound / echocardiography). In addition, cardiac MRI is able to provide detail and measurement of certain heart parameters.
Details of Cardiac MRI Procedure
Who Performs Cardiac MRI?
The cardiac MRI test is performed by a specially trained MRI technologist, with continuous assistance from a pediatric MRI radiologist and a pediatric MRI cardiologist. The input of all these personnel is essential for achieving the most complete cardiac study and explains why testing times are limited.
Interpreting Results
The study will be interpreted in detail by both a pediatric MRI cardiologist and pediatric MRI radiologist. The final report, including detailed numerical analysis and movie clips, will be available to your child's pediatric cardiologist within a few days.
Sedation
Most patients do not require sedation. Some young adult patients do have claustrophobia and difficulty lying in the magnet for a prolonged period. For these patients, it is best to discuss anxiety relief with the ordering physician prior to the appointment.
Breathing instructions will be given during the duration of the exam. It is optimal for the patient to be able to hold their breath when coached, but the scan can be completed without breath-holds. As long as they can remain still and breathe comfortably, children can generally tolerate a cardiac MRI scan by simply watching a movie (on specially equipped “Virtual Reality” goggles) or listening to music. Anesthesia is usually only needed for children less than 6 years of age (depending on the maturity level of the child).
When general anesthesia is required, the Department of Anesthesiology runs the sedation, under the guidance of an attending anesthesiologist.
Child Has Had Metal Clips / Implants Placed. Can He / She Still Undergo a Cardiac MRI?
Metal clips / implant 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, though this is reserved for very special circumstances and requires even more planning and personnel.
Patients will be asked to change into a hospital garment to avoid any risk of metal entering the scanner. If your child has had any metal implanted surgical devices in his / her chest, the devices may obscure areas of the heart and affect usefulness of the imaging. Although this does not always make the procedure unsafe, it may make the results difficult to read. Therefore, in patients with several metal devices and / or coils in the chest, a chest X-ray may be performed prior to 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 required for the MRI. If an IV is necessary, 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 receive a phone call to confirm your appointment 24 to 48 hours prior to the MRI exam. We prepare all patients with specific eating and drinking instructions in case an IV will need to be given during the test. You will also be instructed to arrive 60 minutes prior to 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 him/her as the pictures are being taken. When we start to take the pictures, loud knocking or banging noises will be heard. Whenever your child hears the loud noise, the machine is taking pictures; this is when he / she 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 he/she is OK.
Parents are welcome to accompany their children 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 remain in place until the scan is completed. If your child is unable to hold still for the pictures and he / she was 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.
