MEG Trial RegistrationJanuary 15, 2008
During our second visit to the Neuro-Surgeon did he tell us that a number of checks are required to build a 3D model of my head with the precise location of not only the tumor, but also of the functional areas that are/may be affected by the tumor. The most important checks are the fMRI and the MEG. We were told that the MEG has to take place before the fMRI but not the reason. Now we know.
During the fMRI a strong magnetic field a powerful magnetic field is created which aligns the magnetization of the hydrogen atoms in the body. Radio waves are then use to alter the alignment of this magnetization which cause the hydrogen atoms to emit a radio signal. MEG is an imaging technique used to measure the magnetic fields produced by electrical activity in the brain via extreme sensitive devices. The powerful magnetic field of the (f)MRI may leave traces of magnetism behind that disturb these sensitive devices.
We were informed by the hospital that the trial fMRI, performed with only good intentions to help me deal with the claustrophobia, may have become a reason for a delay in the execution of the MEG. We were asked to come to the hospital for a trial session with the MEG. The Neuro-Surgeon had already told me that the MEG is not on the wish list of people with claustrophobia. I therefore prepared myself by looking for images of a MEG device on Internet. All pictures I could find show a large chair in which you sit and where you have a rather large contraption (a kind of ‘helmet’) on your head. As it was easy to see that ones eyes are not covered did I not worry too much.
However, the reality was different. I had to lie down in a big machine that almost completely covered my eyes, in a room with a very low ceiling and sealed by a door of about 75cm thick. I immediately freaked out. When I wanted to remove my head from the machine I was initially not allowed. “No!” the nurse said. which is not the kind of reassuring response one expects in such situation. After some time was I able to condition myself and did I get somewhat used to the MEG. I stayed about 15 minutes inside and then the nurse told us that the trial fMRI had not magnetized my head. She came back into the MEG chamber but she didn’t allow me to leave immediately, I was forced to lie down inside the machine for another 5 minutes. This definitely did not help.
She told me later that the real MEG will take place on the 23rd of January, that it will take 2 hours (!) and that it will followed by a “normal” MRI. Fortunately I can keep my eyes closed during this “normal” MRI.