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Voiding Cystourethrogram (VCUG)

A VCUG (voiding cystourethrogram) produces images of the urinary tract and shows how it is working.

It uses a technology called fluoroscopy. Fluoroscopy is sometimes described as a “live” X-ray. It shows how internal organs function inside the body.

Doctors request this test for patients who have repeated urinary tract infections or other related problems.

A VCUG can show if the patient has a condition called vesicoureteral (VU) reflux. This condition causes urine to flow in the wrong direction, from the bladder back up to the kidneys. A VCUG can also show if there are any abnormalities or blockages in the urethra.

X-ray image shows beginning of VCUG test in a pediatric cancer patient. 
X-ray shows progression of VCUG test in a pediatric cancer patient.
X-ray shows additional progression of VCUG test in a pediatric cancer patient.
X-ray shows last in series of VCUG test in a pediatric cancer patient.

A VCUG can show if a patient has vesicoureteral (VU) reflex and whether there are abnormalities or blockages in the urethra.

Who performs a VCUG?

A radiologist and a radiological technologist perform the test. Other staff members may help.

How long does the test take?

The test usually takes about 30 minutes.

Is a VCUG safe?

A VCUG is a type of X-ray, so it uses a small amount of ionizing radiation to create images. The amount of radiation given during a VCUG is very small. The medical benefits far outweigh the small amount of radiation exposure. Families should discuss any concerns with the medical team.

Graphic of an adult male body with layover of organs visible. Organs of the urinary tract are highlighted, including the kidney, ureter, bladder, and urethra.

A VCUG produces images of the urinary tract and shows how it is working.

How should parents help patients prepare?

Parents should make sure their child:

  • Understands why he or she is having the test and what will happen. A child life specialist can help prepare and support the patient.
  • Wears loose, comfortable clothing that is easy to take on and off. At most centers, the patient will remove clothing and wear a gown.

What details should be taken care of before the test?

  • Depending on the hospital, parents may need to consult with the insurance company to find out how much the insurance company will pay for the procedure.
  • Parents should tell the medical team about:
    • Any medications the patient takes, including over-the-counter ones.
    • Allergies, especially to iodine. It is in the contrast liquid used during the VCUG.
    • If the patient is or could be pregnant.
  • Allow plenty of time to get to the center. It is important to arrive at the appointment on time, even a few minutes early to allow time for check-in.
  • The parent and patient will stay in a waiting area until it is time for the procedure. Bring activities just in case the waiting period is long.

What happens during a VCUG?

  • A radiology staff member will talk with the family about why the patient needs a VCUG and will explain the procedure.
  • The technologist will help the patient onto an X-ray table. Patients lie on their backs for this test. Infants and young children may have a special device to help them lie still during the imaging. Patients must stay still, or the image will blur.
  • The test requires a catheter, a thin, hollow tube that is placed inside the patient’s bladder.
    • A nurse or technologist will clean the area where the catheter will be placed. This antiseptic may feel cold.
    • A specially trained member of the staff – a nurse, technologist, or doctor - will place catheter inside the patient’s bladder through the urethra. The patient will feel some pressure and may feel the need to go to the bathroom.
    • A nurse or technologist will tape the catheter in place so it does not come out during the exam.
  • The radiology staff member will connect the catheter to a bottle of X-ray contrast liquid. This contrast helps the visualization of the urinary tract, the bladder and urethra in particular, on the fluoroscopy screen.
  • The technologist will pull the X-ray machine, also known as a “fluoro tower,” over the patient’s body. The contrast liquid will flow through the catheter into the patient’s bladder. The technologist will help the patient move from side to side to help get images from different angles.
  • The patient will need to hold in urine even if she feels the urge to go. When the bladder is full, the radiologist will ask the patient to urinate on the table. There will be towels, a urinal, bed pan, or absorbent pad to catch the liquid. While the patient urinates, the radiologist will take more X-rays.
  • The catheter will probably come out on its own when the patient pees. After that, the radiologist will take a few more X-rays.

What will the patient feel during the test?

A VCUG test can be uncomfortable. The insertion of the catheter and filling of the bladder with liquid can cause discomfort.

A VCUG can seem embarrassing and unnatural for children and teens because they are used to going to the bathroom in private. A parent can usually stay in the room with the patient. Also, families can ask for a child life specialist to be there during the procedure.

The radiology staff is experienced at performing the test. It is a necessary medical procedure, so patients need not feel embarrassed.

What will the patient experience after the test?

Some patients have discomfort during urination after the procedure. This feeling usually gets better in less than 12 hours.

How will families find out the results?

The radiologist will interpret the results of the exam and send them to the doctor who ordered the VCUG. A member of the medical team will review the results with the patient and family at the next appointment.


Reviewed: June 2018

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