MRI with Anesthesia

MRI is a routine diagnostic imaging exam that uses a large magnet, radio waves, and a computer to produce 2- and 3-dimensional images of the body's organs, tissues, and bones.

An MRI scan is:

  • Often the imaging modality of choice because it does not use ionizing radiation (X-rays)
  • A way to better evaluate various parts of the body and certain diseases that may not be assessed adequately with other imaging technologies
  • Painless - the MRI scanner takes pictures without touching the body
  • Safe - years of experience have shown no known harmful effects from the magnetic fields and radiofrequency pulses used in this hospital
  • Interpreted by a pediatric radiologist or pediatric neuroradiologist; the results are reported to your child's physician.

How Boston Children's approaches MRI with anesthesia

Sometimes, MRIs need to be performed under general anesthesia. In these cases, the Division of MRI at Boston Children's Hospital provides a soothing, kid-friendly environment with:

  • Highly trained pediatric radiologists with expertise in supervising and interpreting MRI in children of all ages
  • Experienced pediatric anesthesiologists and sedation nurses
  • Technologists with years of experience in imaging children and teens
  • Protocols and procedures specifically for pediatric use, which means age-appropriate care for children and the best possible images for the radiologists.

Frequently Asked Questions

What is an MRI scanner and how does it work?

An MRI scanner is a large, tube-shaped magnet that provides a strong magnetic field around your child. A radiofrequency coil is placed over the body part that is to be imaged. The magnetic field, along with applied radiofrequency waves, temporarily alters the alignment of hydrogen protons found in water molecules within the body. Computers construct the images based on the radiofrequency signals emitted by the protons.

Why might an MRI with anesthesia be needed?

MRI is often used to obtain specific diagnostic information not already provided by other imaging technologies such as computed tomography (CT), nuclear medicine, ultrasound, and X-ray.

Movement will cause the MRI pictures to be blurred. Your child must lie still during the MRI scan. The use of anesthesia will cause your child to go to sleep and remain motionless and comfortable during the scan.

How should I prepare my child for the MRI scan?

While speaking with an anesthesia assessment nurse and scheduling your MRI appointment, you will receive verbal preparation instructions that include dietary restrictions. It is very important that you follow all these instructions or the scan may need to be rescheduled.

It is helpful to give your child a simple explanation as to why an MRI is needed. You may want to bring your child's favorite book, toy, or comfort object to occupy him or her during waiting times.

What should I expect when I bring my child to the hospital?

When you arrive, please go to the MRI radiology check-in desk on the second floor of the main hospital. An patient experience representative will check in your child and verify his or her registration information.

We will give you safety screening questionnaires to fill out for you and your child:

  • This form will ensure that your child can be safely imaged in MRI
  • Please bring supporting documentation of MRI safety if you or your child have had any surgical implants or devices. Delays may result if devices need to be researched. Some exams may need to be cancelled if the required MRI safety information cannot be obtained.

What happens in the MRI exam room?

When your paperwork is complete, you will be taken to an MRI exam room where:

  • A member of the nursing team will weigh and measure your child
  • Your child will change into hospital pajamas
  • You and your child will need to remove all metal objects. Lockers are available for locking up any valuables.

Your sedation nurse will:

  • Confirm that all preparation instructions were followed
  • Review your child's health history and current health status and medications
  • Check your child's temperature, heart rate, breathing rate, blood pressure, and oxygen level, and listen to his or her lungs.

All females who have begun their period, or who are over the age of 12, will be required to provide a urine sample for a pregnancy test.

It is important to notify the nurse of any active or recent illness, allergy, or previous drug reaction. You are encouraged to ask questions throughout the process.

How is the anesthesia administered for MRI?

Once the sedation nurse has finished examining your child, the anesthesia team will:

  • Speak with you about your child's health history and status and perform a brief physical exam to confirm that your child can be safely anesthetized.
  • Discuss the best anesthesia plan for your child.
  • Administer the anesthesia and monitor your child throughout the exam and recovery.

When the anesthesia team members have completed their exam, your child will be transported into the scanner room. If the anesthesiologist determines that you can accompany your child into the scanner room (only one parent would be allowed), you will be allowed to stay in the room until your child is asleep. You will then be escorted to the waiting area.

What happens during the MRI scan?

Once your child is asleep:

  • The anesthesia team and MRI technologist will position your child on the scanning bed. The inside of an MRI machine looks like a tunnel. It is necessary for the body part that will be scanned to be in the center of the scanner, so the technologist will move the scanner bed into the tunnel until it is appropriately positioned.
  • We will place earplugs on your child to protect his or her ears because the MRI machine makes loud pulsing or knocking sounds.

An MRI technologist will perform your child's scan and the anesthesia team will continue to monitor your child.

Sometimes, patients receive a substance called gadolinium during the scan, which is needed to provide additional information about some parts of the body. Gadolinium is given through the IV.

MRI scans consist of several sequences of a few minutes duration each that cumulatively take anywhere from 20 to 90 minutes, depending on the information required by the radiologist and your physician. We will give you a more specific time frame before the scan begins.

What does an MRI sound like?

Sound 1
Sound 2
Sound 3
Sound 4
MR makes music!

What happens after the MRI scan?

When the MRI scan is done:

  • The anesthesia team will bring your child to the MRI recovery room, where he or she will continue to be monitored until discharge.
  • The recovery room nurse will give your child fluids through the IV.
  • After about 15 minutes, the recovery room nurse will begin waking your child. Once he or she is awake, some juice or crackers may be given.

When your child is ready to go home:

  • The recovery room nurse will remove the IV and monitoring equipment.
  • You will be given discharge instructions with contact information in case you have any questions or problems after leaving the hospital.
  • Your child may still be sleepy, so it is important that you help him or her to prevent falling.

A wheelchair with a safety strap will be used to transport your child to the car. You and your child may not walk or take public transportation after this appointment. A recovery room nurse will call the next morning to make sure that your child has fully recovered from the anesthesia.

The radiologist will review the images and create a report of the findings and diagnosis for your referring doctor.

How do I learn the results of the MRI scan?

The radiologist's report will be sent to the physician who requested the exam and your child's doctor will then discuss the results with you. If there is a finding on the scan that requires urgent attention, we will contact the referring physician in order to discuss the findings and plan further treatment.