UserX
You can get an ultrasound but I would stick with - "do two in 3 weeks, if they both come up clear - you're probably ok".
I prefer the epsom, olive, and grapefruit flush for the best results. For a more long term maintenence - Schulze's flush is good (ginger, garlic, olive, juice and water).
You can dissolve stones with apple cider vinegar w/mother. I take a few tablespoons in distilled with some cayenne - always after dinner and more often if possible. The big expensive racehorses are prone to stones (Enteroliths) - they get apple cider vinegar to stop them. Big $ is saved when a big $ horse doesn't die bacause of a blockage.
see:
http://www.harcourthealth.com/communities/Veterinary/Mansmann/enter...
and
http://www.angelfire.com/falcon/reed/enterolith.html
Question is why horses get this and we don't: Horses are worth more healthy - humans are worth more ill. Sad and scary but oh so true.
_BOB