Firstly, I am sorry you are having this worry at all.
I agree with other PPs, that you are right to be concerned about a GA and rest assured your LO would be having it only because it is absolutely necessary. And I agree with Onyx that the dr was rude not to take your concerns into account. The anaesthetist may be more human in explaining the minimal risks to you - you can contact the radiology practice and ask who the anaesthetist will be and get in contact with them to discuss it first if you like. It is your right.
I work for a neurosurgeon and he can be a jerk sometimes. They work long hours and under stressful conditions. But most of the time he is great. Perhaps your surgeon was having a bad day. Make sure you make the most of your appointments. If you have questions, ask them. If you are worried about risks, ask about them and what the chances of them happening are. Inform yourself, if you think that's what will be best for you. Don't take any garbage - he is just a person like you and he needs to do his job properly. Most likely you are paying him a small fortune to consult with him so explaining everything in detail is the very least he can do, frankly.