What are the uses of US in gall stones?

Tests for cholelithiasis (mobile stones in gall bladder, echogenic, best test for stones in gall bladder) Choledocholithiasis (stones in bile duct, we could se dilated BD >6mm w/ or w/out stones) Acute cholcystitis (Murphy's sign [palpate gall bladder and pain is felt], when stones are seen confirm it