An ultrasound will show if the liver has atrophied (shrunk/become smaller) at this point and it will also show if there are stones/crystals in the bladder which is usually secondary to liver shunt/liver disease. Other than that, it's very difficult to actually see if there's a liver shunt with a sonogram.
What supplements and food were you giving her exactly before you found out about this?
If you can join the liver shunt and mvd group on yahoo groups, it would probably be beneficial to you. In the Files section we have an extensive amount of information which you can print up and take to your vet if you like. The people on there are very knowledgable about liver shunt and liver disease, and you can get advice and help.
Liver_Shunt_And_MVD_Support : Liver Shunt & MVD/HMD Support