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24.03.2010
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MEG Exam Step by Step

Pre-exam Doctor's Appointment: 
Previous to the MEG exam the patient will arrive at the MEG clinic for a doctor's appointment. At this time the patient is required to bring medical history and references such as: previous tests conducted, letter of referral from the epileptologist, MRI, and information about previous surgeries, is such occurred. 
The patient will be asked to describe the epileptic seizures, auoras-if such happen and the seizure frequencies. All such medical information and history, helps the doctor plan the MEG test. 
In some patients that have non-removable metallic devices such as: orthodontic equipment, vagal nerve stimulator or that have previously been operated on the doctor may choose to perform an "artifact test" – short MEG recording aimed at testing the magnetic interference. 
During this appointment, the patient will be asked to fill out some paperwork. 

MEG Exam Step by Step

Step 1: 
Marker coils are placed on the patient's head. These coils record the position of the head during the test. The nasion is marked for later use. This point will "register" the MEG information with the patient's MRI information. 

 

Step 2: 
EEG wires are glued onto the patient's head. The EEG, ECG and EMG can give information to monitor heart rate, count eye blinks, or record electrical impulses from the brain and muscle. 
 
 

Step 3:
The patient enters the Magnetically Shielded Room (MSR), and the location of the coils are put into digital form. This process defines the head frame of reference. Then, the shape of the patient's head is also put into digital form to begin the MEG process. 
 

Step 4: 
The patient is then placed in the MEG system and made comfortable. If a somatosensory test is being conducted, finger tappers are placed on the hand and are activated during the scan. If a language test is being conducted, the patient will either hear words or see letters and pictures on a screen. If an epilepsy test is being conducted, the patient needs to relax and lie still. 
 

 

Step 5: 
Once the patient is in the system, the staff can monitor the patient via an intercom system and a video monitor. During this completely painless and non-invasive test, the staff can view real time MEG data along with the EEG data. When the test is completed, all coils and wires are removed and the patient can leave with no restrictions. 

 


 


Step 6: 
After the patient leaves, the data from the MEG exam is reviewed and analyzed. MEG source localizations are then overlaid onto the patient's MRI and a report is generated for the referring physician.