navyard,
thanks for the post.
1) My question is can the results change this much or is it all in the interpretation? How do you know which one is accurate?
From the way it sounds this sounds pretty close and withing the window of interrader variability. Remember, these are interpretations of the pictures, so there is some variability between readers. The important thing is that minor variations really carry no significance and what is more important is significant progression over time. Both readers are probably correct. You should discuss the result fo both studies with whomever your primary physician is now to ensure this is the case.
good luck