Did you ask for a copy of the report? It is very important so you can see where the stone is, besides you want to know the size. It will also give you other information, MD's only give you what they want to tell you.
When I read my report in 2003 the stone was in the gallbladder neck and was almost 1", there was inflammation and the wall had thickened. I flushed and did another US in 10 months and the inflammation was gone, the wall was back to normal and the stone was free floating.
I still have the stone probably because it is almost the size of the gallbladder and it can't contract enough.
I just have to hope it does not get bigger.