Constant pressure flow-controlled antegrade pyelography.

Flow-controlled antegrade pyelography is performed by perfusion of contrast dye after transcutaneous puncture of the renal cavities. The procedure enables excellent visualization in cases of upper tract dilatation, when the result of high-dosis excretory urography is not satisfactory. Flow-controlled antegrade pyelography under constant pressure provides urodynamic support to pyelography because the flow rate is known during the procedure, facilitating the interpretation of the relation dilatation and flow in cases of upper tract equivocal obstruction. Perfusion under constant pressure enables the recognition of the resistance to flow of the pyeloureteral tract in a simple manner.