[joy and bella]

Ok, sooo I just received a very very strange phone call from the vet- they said they did 2 x-rays and that they cannot see a stone?!?!?! She said that about 90% of stones show up on an x-ray and about 10% you cannot see or are too small to see. She said that she doesn't see any reason to open her up for surgery right now. She said she is going to do a urine sample to see if there is any blood or crystals in her urine, but other than that my only option is to do an ultrasound, which will cost about $325!!!!! I am just so confused?!? The other vet saw the stone with the ultrasound.....is it possible she passed it????? I really do not know what to take from this right now......