Magnetoencephalography (MEG)

The newly opened Magnetoencephalography (MEG) laboratory at Dell Children’s Medical Center provides advanced state-of-the-art brain mapping technology within a world-class laboratory and is poised to become a premiere site in Texas for functional neuroimaging.

What is magnetoencephalography or MEG?

MEG is a non-invasive (no shots or radiation) brain imaging technology that can identify the exact location of essential brain functions such as those involved in controlling the hands and feet, processing speech, sense of touch, or vision. MEG can also localize seizures and other types of abnormal brain activity. With this combined information, surgical procedures can be planned to remove diseased brain while minimize damage to parts of the brain that are working correctly.

How does MEG work?

MEG passively records very tiny magnetic fields produced by naturally occurring brain activity. Using advanced methods, we can determine where in the brain functions occur. The results are combined with the patient’s MRI to construct a “Functional Brain Map” to help physicians develop a treatment plan.

Who would benefit from a MEG?

MEG can benefit many people who have chronic neurological problems or may need brain surgery.

  • Children with medically refractory epilepsy
  • Patients diagnosed with a brain tumor
  • Any patient who has consulted with a neurologist and neurosurgeon about brain surgery

How long does a MEG scan take?

The amount of time it takes to complete a MEG scan varies from person to person. However, patients should be prepared to be at Dell Children’s Medical Center for anywhere between 3-5 hours. During this time, there will be long stretches where the patient will be asked to lay still, but there will be opportunities for breaks. Patients needing anesthesia may involve additional time commitments.

How to prepare for a MEG

As an outpatient procedure, preparing for a MEG scan is minimal and often well tolerated by patients. In an effort to have a successful scan, we ask that the patient arrive sleep deprived or tired in hopes of recording his or her brain activity in the awake, drowsy and sleep states. The patient can eat normally before the scan and should take medications as usual, unless told otherwise.

Because metals can interfere with the scan, the patient should not wear any clothing with metal zippers or snaps above the waist and shouldn’t wear jewelry or a wrist watch. Electronic items with a magnetic strip also aren’t allowed. Please notify MEG department personnel in advance if the patient wears braces or a permanent retainer, or has an electronic implant, such as a pacemaker or a vagus nerve stimulator (VNS).

Other suggestions in preparing the patient for the MEG scan include:

  • Avoid caffeinated drinks (soda, coffee, tea) the morning of the test
  • The night prior to the test, wash the patient’s hair, but avoid hair products (no conditioner, oil, gel, mousse, or hairspray)
  • No underwire bras
  • No makeup, lotion, or creams to the face or body
  • Glasses will be removed prior to the test; contact lenses are OK
  • A “blankie” or stuffed animal (without metal components) can be comforting for children

What to expect during a MEG scan

When the patient arrives for the MEG scan, they may have EEG electrodes placed on their head if the physician has ordered it. The technician will then lead the patient into the room where the scan will take place, help them get onto the bed and position their head properly for the scan. Their head will be in the scanner, but their face won’t be covered and they will still be able to see. Once positioned in the scanner, they may be asked to lay still, watch flashing lights or move their fingers. The scanner doesn’t make any noise and the patient won’t be able to tell when the scan has begun. Once the scan is done, the technician will come help them out of the scanner.