Voiding Cystourethrogram

What is a Voiding Cystourethrogram (VCUG) test?

A voiding cystourethrography (VCUG) is an imaging study that allows us to evaluate the functioning of your child’s bladder, urethra, and kidneys, and to detect reflux (a condition in which urine backs up to the kidneys instead of flowing out through the urethra). Doctors often request this study in children who have urinary tract infections, difficulty voiding, or neurogenic bladder, a condition in which children lack bladder control because of a brain, spinal cord, or nerve problem.

A VCUG is a fluoroscopy exam. This type of X-ray imaging enables doctors to capture a real-time, moving image of your child emptying his or her bladder, much like an X-ray movie. To make this image we use a specialized X-ray machine called a fluoroscope. The fluoroscope directs an X-ray beam at the part of the body to be examined, and captures the image as the X-rays are absorbed or scattered by the internal organs and tissues. During the exam your child will be asked to lie on a table below the X-ray machine and detector. To highlight the contours and function of the bladder we will use a catheter to fill the bladder with a liquid “contrast agent.” The liquid contains an X-ray absorbing agent that appears white on X-ray film.

How should I help my child get ready for the test?

On the day of the test your child should wear comfortable clothes, and will be asked to change into a gown when he/she arrives at the fluoroscopy site.

What will happen during the test?

To introduce the contrast dye into your child’s bladder we will place a small flexible catheter (a hollow plastic tube) up through the urethra into the bladder. (In boys we pass the tube through the penis). We will then slowly drip the contrast dye through the tube to expand the bladder. When the bladder is fully expanded, we will ask your child to empty (void) his/her bladder onto an absorbent pad on the X-ray table. As your child voids we will record the process with the fluoroscope.

How can I help my child feel comfortable about and during the test?

While the diameter of the catheter is smaller than the urethra, the passage of the catheter may be uncomfortable, particularly if your child is unable to relax. We sometimes have to immobilize a child so that we can position the catheter properly. We do this by wrapping his/her legs with an ace bandage and we will ask you to hold your child’s hands. Many children, particularly those who have recently been toilet trained, are disconcerted by having to void under the camera.

Young children sometimes find the fluoroscope, a large machine that passes over the X-ray table, a bit frightening. You can remain with your child in the imaging area during the exam to offer comfort and reassurance and will be asked to wear a lead apron to protect you from unnecessary exposure to radiation. We can also arrange to have a child life specialist at your child's appointment to help your child better cope with the stress of the procedure.

Are there any risks?

Although this is an X-ray based exam, your child will be exposed to minimal doses of diagnostic radiation.

After the test

A radiologist will analyze the fluoroscopic images and will share the results with the doctor who requested the exam. Your child’s doctor will then discuss the results with you.