The hospital is duty bound to hand over copies of all films - whether they be on cd or hard copy - and both medical and surgical record / transcripts. Just go back there and insist that they hand over whichever of those things you want. Most often, they don't offer them to you or invite you to take them; you have to ask for them yourself.
As far as the problem that you're having with the cd right now - I couldn't tell you, having full, big-sized copies of the negatives. Just call the radiology dept. and ask them. I've had four MRIs so far, but only have the copies from my first session. Later this year, when I go back home, I'm going to request all of them, including my surgical records.