A detailed X-ray study of the bladder. The test may be performed when an infection, tumor, bladder stones, or reflux of urine into the kidneys is suspected. The patient first empties his or her bladder by normal urination. Then, a thin, flexible tube (catheter) coated with anesthetic jelly is inserted through the urinary tract. The bladder is filled with dye through the catheter, and X rays are taken with the patient in different positions. The patient voids the dye by urinating, and another X ray is taken. Voiding cystography is not painful, but it can be uncomfortable. After the test, the patient may experience tenderness in the urinary tract for 24 hours. There is a small risk of infection marked by chills, fever, and burning during urination after the first 24 hours.