Is it true that adjustment of the ventricular shunt valve is required only after an MRI?

In my experience, an MRI can cause more of a problem than a help. You have to be very careful on the type of shunt that you have. If it is a particular type( I think it is the Codmans) you can't have a MRI. The reason for this is that it changes the pressures.

The only reason that I know this, is that it has happened to me on a few times, before we figured out why the pressures were changing.