MEG test or Magnetoencephalography/Magnetoencephalogram is an advanced diagnostic aid which has the capability to utilize the combined benefits of an EEG (electroencephalogram) and an MRI (magnetic resonance imaging) scan to study the brain and its electrical activity. It is a painless and non-invasive test of high precision value.
What is MEG test ?
MEG test or magnetoencephalogram is an advanced diagnostic test which is used to evaluate the electrical activity of the brain and localize the areas where there is a problem. It can also help in localizing the neurons which could be responsible for the change in the electrical activity of the brain. In a MEG test the electrical activity of the brain is analyzed with the images obtained by an MRI scan thereby helping in the exact location where the electrical activity is abnormal. This test is a high precision test and requires trained and experienced professionals.
When is MEG test advised ?
MEG test is advised in individuals where radiation exposure is not advised. It is advised to evaluate the brain and the neuronal activity and in individuals who are affected with certain brain disorders like epilepsy or before a neurosurgical procedure to map the exact surgical site. In epileptic patients MEG test helps in determining the exact location from where the seizures are being initiated.
How do you prepare for an MEG test ?
A MEG test is advised by your neurologist or your neurosurgeon after a complete evaluation of your overall health, signs and symptoms, past and present medical history. Your medication history is also evaluated and the medicines which need to be modified or stopped before the procedure. The test is performed in an electrophysiology laboratory or a magnetically equipped lab. You can either get admitted as an in-patient or take appointment for an outpatient procedure, but you will need someone to drive you back home.
No anesthesia or sedation is ideally used during the test, but if sedation is advised you might be asked to keep your stomach empty before the test. You will be asked to wear loose clothing or change into hospital gown before the start of the procedure. You will also be asked to remove any items like coins, belts, hearing aids etc. or substances which could get influenced by the magnetic field. It is important that you inform your doctor if you have a metal implant or a pacemaker.
How is the MEG test performed ?
A trained team of neurologists, radiologists and technicians perform MEG test. A magnetic videotape eraser will be moved around your head to remove any magnetic field around the head. EEG electrodes will be placed all over your head at the required places. ECG (electrocardiogram) electrodes will be attached to your chest to monitor the activity of your heart during the test. You will be made to lie down on the examination table and few magnetic coils will be attached to your forehead. These coils and electrodes record the shape of your head. Once the electrodes are successfully placed you will be asked to lie down comfortably and to not move during the test. You will be asked to talk something before the procedure to and sensations will be generated to hand and feet to activate the areas of the brain which are responsible for generating electrical impulses of sThe test room door will then be closed and you can communicate with your doctor or the technician via a microphone. The test takes about 1-2 hours to complete. It is important to tell your doctor in advance if you are claustrophobic. The activity of your brain is recorded and the areas with the affected electrical activity are analyzed.
Sometimes, MRI imaging/ structural imaging is combined with the test and the procedure is collectively termed as Magnetic Source Imaging (MSI). This helps in localizing the areas of the brain where the electrical activity is affected. This is used in identifying the areas where the seizure is generated in epileptic patients.
Who reports the MEG test ?
The MEG test is reported by your neurosurgeon or neurologist depending upon the requirement or as per the reporting policy of the healthcare facility.
What are the risks and complications of a MEG test ?
MEG test is a safe procedure as it does not utilize any ionizing radiation and is a non-invasive as well. This procedure is safe in children and pregnant women. Individuals who are claustrophobic or have fear of closed spaces should inform their treating doctor well in advance as the duration of the test is quite long and one can take breaks during the test of required.
Disclaimer: The content provided here is meant for general informational purposes only and hence SHOULD NOT be relied upon as a substitute for sound professional medical advice, care or evaluation by a qualified doctor/physician or other relevantly qualified healthcare provider.
