A cystourethrogram is an X-ray test that takes pictures of your bladder and urethra while your bladder is full and while you are urinating. A thin flexible tube (urinary catheter ) is inserted through your urethra into your bladder. A liquid material that shows up well on an X-ray picture (contrast material) is injected into your bladder through the catheter, then X-rays are taken with the contrast material in your bladder. More X-rays may be taken while urine flows out of your bladder, in which case the test is called a voiding cystourethrogram (VCUG).

If X-rays are taken while contrast material is being injected into the urethra, the test is called a retrograde cystourethrogram because the contrast material flows into the bladder opposite the usual direction of urine flow.

Why It Is Done

A cystourethrogram is done to:

• Find the cause of repeated urinary tract infections.
• Look for injuries to the bladder or urethra.
• Find the cause of urinary incontinence.
• Check for structural problems of the bladder and urethra.
• Look for enlargement (hypertrophy) of the prostate or narrowing (stricture) of the urethra in men.
• Find out if urine is flowing the wrong way, from the bladder back towards the kidneys (vesicoureteral reflux). See a picture of abnormal urine flow .
• Look more carefully at abnormalities first found by intravenous pyelography.

How To Prepare

Tell your doctor if:

• You are or might be pregnant.
• You have symptoms of a urinary tract infection.
• You are allergic to the iodine dye used in the contrast material or any other substance that contains iodine. Also tell your doctor if you have asthma, are allergic to any medicines, or have ever had a serious allergic reaction (anaphylaxis), such as after being stung by a bee or from eating shellfish.
• Within the past 4 days, you have had an X-ray test using barium contrast material, such as a barium enema, or have taken a medicine (such as Pepto-Bismol) that contains bismuth. Barium and bismuth can interfere with test results.
• You have an intrauterine device (IUD) in place.

This test is often done in children to see if they may have an abnormal backflow of urine (vesicoureteral reflux). Prepare your child for exams and tests that are needed. Doing so will help your child understand what to expect and can help reduce fears.

You may be asked to sign a consent form authorizing this procedure. Talk to your doctor about any concerns you have regarding the need for the test, its risks, how it will be done, or what the results may mean. To help you understand the importance of this test, fill out the medical test information form(What is a PDF document?).

If you are breast-feeding, give your baby formula for 1 to 2 days after the test.