(((((((((((((((tpetralia)))))))))))) I'm so sorry for what you've had to go through. The thing with taking too much valium or any other kind of relaxer drug is that you have to be aware enough to not move during the MRI. So if you took too much, you might jerk your head as you fall asleep or your head might slip to the side.

Perhaps you can talk to the dr beforehand and explain the situation to him and ask if you could try to take more at home before the procedure so that you will know how it will affect you?

Also, like bebop said, focusing on something else can help. I also sing every single song I can think of during them (usually my head ends up singing children's songs). Best of luck to you and please keep us posted.