I would do a CT Scan with contrast, that way if there is an actual blockage or narrowing somewhere they can see this and would know which way to pursue the treatment. I assume he is a specialist (since he said he could break it up) X rays and ultra sounds are not always the best test for everything. If the stone is sitting just right, it may not show up. So I would talk to him about the CT Scan as this point and go from there.
Hope this helps.
