A voiding cystourethrogram is a test that is done to see if there are problems with the bladder or other parts of the urinary system. It uses contrast liquid and X-rays so the doctor can see the size of the bladder and how the bladder fills and drains.
This test can show if urine from the bladder is flowing back up toward the kidneys. This is called vesicoureteral reflux, or VUR.