its best to get the xrays done then have the crystals sent to a lab to see what kind they are. theres different prescripyion foods for different stones.
my vet played the guessing game and made it much more worse on my Yorkie.
they sedated. They took 4 xrays. No big stones but lots and lots of Crystals, Blocking his urine. They put in cathider to empty his urinary bladder. Then, they examined crystals and filled him back up with water to push back the blockage of Crystals. They put him on antibiotis and S/D prescription diet food to help with dissolving the Crystals but this only helped for awhile and he ended up blocked up once again. and they did the same thing to him. I had had enough and told them this is not working we need surgery. so they agreed and he had sugery but 6 months later they were back and he had to have surgery again. he is now to stay on S/D prescription diet food and only drinks bottled water. so far so good.
heres afew sites that I read and have helped out alot.
Bladder Stones Prescription Diet: Therapeutic Pet Food for Cats and Dogs | Hill's Pet Nutrition
and heres all are threads with alot of info on them if you have time to go through them all.
http://www.yorkietalk.com/forums/off...eep-up-me.html