What diagnostic methods are currently available for upper urinary tract obstruction?

The presence of zipper urinary tract obstruction, its site and its nature c an be determined and the most appropriate treatment can be defined in the m ajority of clinical cases. However in some circumstances, non-invasive or m inimally invasive methods, such as ultrasonography, intravenous urography, urography with diuretic test, conventional and diuretic nephrography and MR urography, are unable to confirm the presence of obstruction, requiring as sessment of the tipper urinary tract by antegrade pyelomanometry. This inve stigation measures the pressure in the tipper urinary tract perfused at a c onstant rate by a percutaneous catheter and allows evaluation of the obstru ction. The authors discuss the place of the various upper urinary tract inv estigations to confirm the definitive diagnosis of tipper urinary tract obs truction.