Pat,
I'm the person Marianna is likely referencing as mentioning "enhancing" on MRI"s on Mary's post about physicians not being too helpful post surgery. Enhancing is about tissue lighting up white in a certain area for some reason. At any rate, I am not a doctor. I used to work in the radiology field as a radiographer or technician, the person whom does the imaging. The reason you are enhancing or not enhancing and the relationship to you and your tumor is likely a different story then mine. You need to ask questons specific to your concerns straight away to your doctors. If I can help you ask better questions I'm happy to help sort this out if at all possible. For example, is the tumor now stable or dying? It sounds like if you are getting decreased enhancement you may be showing progress in a positive direction. This likely has nothing to do w/your headaches but still positive news regarding your tumor. I'm just guessing, remember I'm not a doctor and I'm not trying to play one on the internet. But if you were getting more enhancenebt initially this would likely be due to the tumor reacting to the radiation which is exactly the purpose of the radiation. Now that the tumor is dying or stable you have less enhancement at least thats what it sounds like to me. Those of us whom may have chronic post craniotomy headaches, this is likely relative to the surgery itself which I'm guessing is a different story from those whom had gamma knife treatment. It makes sense to sort out what's causing your specific headaches, check your c-spine etc.
I wish you well!