The urine can go backwards and cause backpressure on the kidneys, or hydronephrosis at children which are born with immature ureter valves. In the case of abnormality presence some tests are recommended by doctor. Outlining the structure of the kidneys on x-ray is shown by the dye that travels through the kidneys and into the urine. If VUR is present the x-ray will show the dye backing up through the ureters into the kidneys. Intravenous pyelogram (IVP) involves injected dye through an IV into the blood stream.