A voiding cystourethrogram (VCUG) is an exam that takes images of the urinary
system.
The patient's bladder is filled with a liquid called contrast material. Then, images
of the bladder and kidneys are taken as the bladder fills and also while the patient
urinates (pees). These images help doctors see problems in:
the bladder, the muscular sac in the lower belly that holds pee
the urethra (yoo-REE-thruh), the tube connecting the bladder with the outside
of the body
the ureters (YUR-uh-ters), the tubes connecting the kidneys to the bladder
How Is a Voiding Cystourethrogram Done?
The images for a voiding cystourethrogram (siss-toe-yuh-REE-thruh-gram) can be
taken two ways: with an X-ray or an ultrasound.
X-Ray
An X-ray machine sends beams of radiation through the belly and images are recorded
on a computer. X-ray images are black and white. Some body parts, such as bones, appear
white on the X-ray. Some body parts, such as the kidneys and bladder, are hard to
see on an X-ray. But the contrast material used for the test makes it much easier
to see the urinary tract on the X-ray.
A radiologist takes the X-rays using a technique called
. While the contrast material fills the bladder, and then while the patient
empties the bladder, the technician or radiologist watches an onscreen X-ray video
of the liquid moving through the urinary system and a series of X-ray images are recorded.
Ultrasound
Another way of doing a VCUG is with ultrasound.
The sonographer places warm gel on the belly and an ultrasound probe on the patient's
skin to get images. The bladder and kidneys are watched with the ultrasound and images
are taken as the bladder is filled with contrast. Ultrasound is different from X-rays
because it does not use radiation.
If your child needs a VCUG, your doctor will help decide which method is right
for your child.
Why Are Voiding Cystourethrograms Done?
A VCUG can check for problems in the structure or function of the urinary system.
It can check the bladder's size and shape and look for problems, such as a blockage
along the path of the urine.
It also can show whether pee is moving in the wrong direction. Normally, pee flows
from the kidneys down to the bladder through the ureters. When it goes the wrong direction
(back up toward the kidneys), it's called vesicoureteral
reflux (VUR). A VCUG can detect VUR. Sometimes this problem only happens when
a person is urinating (voiding). That's one reason why the VCUG must include taking
images while the bladder is being emptied.
Because VUR can cause urinary
tract infections (UTIs), this test is sometimes recommended after a child has
had a UTI. Not all kids who have had UTIs have reflux, but it's important to find
those who do, because treatment may vary depending on the severity of reflux.
How Do We Prepare for a Voiding Cystourethrogram?
Some children over 1 year old may get sedation for the test. If your child has
sedation, they must not eat or drink before the test. Talk to your doctor about whether
sedation is needed.
Otherwise, a VCUG doesn't need any other special preparation. Your child may be
asked to remove clothing and jewelry and change into a hospital gown because buttons,
zippers, clasps, or jewelry might interfere with the images.
If your daughter is pregnant, it's important to tell the technician or her doctor.
X-rays are usually avoided during pregnancy because there's a small chance the radiation
may harm the developing baby. But if the X-ray is needed, precautions can protect
the fetus.
It's also important to tell the technician if your child has any allergies, especially
to contrast material.
What Happens During a Voiding Cystourethrogram?
A VCUG takes about 30–60 minutes.
The test is done in a special room with either an X-ray or ultrasound machine.
Parents usually can stay with their child during the VCUG. A doctor also will be there,
as well as either an ultrasound or X-ray technician.
The technician or doctor will wash between your child's legs, then insert a tiny
rubber tube called a
into the bladder through the small opening of the urethra (where pee comes
out). This might feel uncomfortable. When the catheter is in place, the rest
of the test usually is painless.
The catheter is used to fill the bladder with the contrast material. As the bladder
fills, it's viewed on a screen and pictures are taken. Your child will start to feel
the need to pee as the bladder gets full. Babies will empty their bladder automatically.
Older kids are asked to hold it in until the bladder is full. Then, they're asked
to pee. The movement of the contrast material in the urinary system is seen on the
screen and pictures are taken. When the bladder is empty, the catheter is removed.
Your child won't feel anything as the images are taken. Babies do often cry in
the exam room if they are being held still for the pictures, but this won't interfere
with the procedure.
Your child might complain of stinging while peeing the first few times after the
test. Drinking extra fluids can help.
When Are the Results Ready?
A radiologist (a doctor trained in reading and interpreting X-ray and ultrasound
images) will review the images. The radiologist will send a report to your doctor,
who will discuss the results with you and explain what they mean.
In an emergency, the results of a VCUG can be available quickly. Otherwise, results
are usually ready in 1–2 days. In most cases, results can't be given to the patient
or family at the time of the test because the images need to be reviewed in detail.
What Are the Risks of Voiding Cystourethrogram?
In general, X-rays are very safe. Although there is some risk to the body with
any exposure to radiation, the amount used in a VCUG is small and not considered dangerous.
It's important to know that radiologists use the lowest amount of radiation needed
to do the test.
If the test is done with an ultrasound, there is no radiation. Ultrasound is very
safe and the FDA has approved the contrast material for use in VCUG studies.
How Can Parents Help?
You can help your child prepare for a VCUG by explaining the test in simple terms.
If your child is old enough to understand, be honest about the brief discomfort they
may feel, but reassure your child that you'll be there for support. A mild sedative
can make the catheter placement easier for toddlers and preschoolers (and some older
children). Ask your doctor about sedation if you think it might help your child.
You can describe the room and the equipment that will be used. With older kids,
explain the importance of keeping still while the images are taken so they won't have
to be repeated. It may help to explain that after the catheter is in place, getting
the images is like posing for a picture or a video.
Some kids need a distraction (toys, books, bubbles, etc.) during the test, while
some want to watch what's going on. Others may cry and might need more reassurance.
If you have questions about why the VCUG is needed or how the test is done, speak
with your doctor. You can also talk to the technician before the procedure.
