DCIS and surgery

I had a digital mammogram; as far as I know a regular one. No-one has ever explained a difference. Nothing showed in the ultrasound either, but the Dr only ordered it for the breast in question, not both. The surgeon says that it's next to useless if she can't make comparisons to the other breast. I'm hoping the MRI will show whatever is going on. I'm finding it really hard to be brave. I don't even have a diagnosis and I'm already freaking. I think I expected her to tell me definitively that it wasn't DCIS rather than tell me it could be. I have never heard of tomosynthesis. I will look it up immediately. The surgeon said there was only 3% increased chance of picking something up with the MRI compared to ultrasound (which showed nothing). What worries me most though is misdiagnosis or spreading cells via this duct removal.