Voiding Cystourethrogram (VCUG)

  • The voiding cystourethrogram (VCUG) test produces pictures of the urinary system.
  • An X-ray and an ultrasound are two medical imaging procedures that can produce images for the voiding cystourethrogram.
  • There are numerous variations of VCUG to improve disease visualization while minimizing radiation exposure.
  • While a VCUG procedure is generally safe, some individuals may experience adverse reactions. Patients need to inform their doctors about their health status in detail.

What Is Voiding Cystourethrogram?

Voiding cystourethrogram (VCUG) is a marginally invasive test that typically uses fluoroscopy, a type of X-ray technology, to visualize a child’s bladder and urinary tract.

Common Uses of the Procedure

A child’s VCUG is necessary when(1):

  • Diagnosing vesicoureteral reflux, a condition in which urine flows backward from the bladder to the kidneys
  • Examining the child’s urethra for any abnormalities or blockages
  • Identifying the cause of a child’s recurrent urinary tract infections
  • Assessing the effectiveness of antibiotics or anti-reflux surgery

The voiding cystourethrogram typically uses an X-ray or an ultrasound to obtain images(2).

About Vesicoureteral Reflux (VUR)

Vesicoureteral reflux or VUR occurs when a defect in the valve or the ureters allows urine to flow backward(3)

In mild cases, urine backs up into the lower ureter. However, the urine can go back up into the kidneys in severe cases.

Usually, the kidney produces urine and flows through the ureter, connecting each kidney to the bladder. When the bladder fills up, a valve prevents urine from backing up the kidneys. 

Urine leaves the bladder via the urethra during urination before it exits the body. Several causes of VU reflux include(4):

  • Genetic condition
  • Bladder blockage
  • The bladder not being empty
  • Unusual urination with extremely high bladder pressure


Some children over the age of one may undergo sedation for the test. Children undergoing sedation should not eat or drink anything before the test.

A VCUG does not require any special preparation. However, buttons, zippers, clasps, or jewelry may interfere with the images, so a child life specialist may ask your child to remove clothing and jewelry and make them change into a hospital gown.

Child life specialists are healthcare experts who assist children and families cope with diseases, injuries, disabilities, trauma, or hospital stays(5).

A pregnant patient must inform the technician or the child’s doctor about her circumstance. 

Practitioners typically avoid using X-rays for pregnant patients because a specific amount of radiation may harm the developing baby. However, healthcare experts can take specific precautions to protect the fetus if an X-ray is necessary.

Furthermore, it is also critical to inform the technician if the child has any allergies, particularly contrast material.



An X-ray machine sends radiation beams through the stomach, which the computer then records. X-ray pictures are black and white. 

Several body parts, such as bones, appear white on an X-ray. Other body parts, like the kidneys and bladder, are challenging to see on an X-ray

However, the contrast material used in the test makes the urinary tract much easier to see on an X-ray.

During VCUG fluoroscopy, a children’s (pediatric) technician or radiologist observes an onscreen X-ray video of the fluid moving through the urinary system. Specialists perform this procedure while the contrast material fills the bladder and while the patient unloads the bladder.

A recording of successive X-ray images also occurs during the procedure above.


An ultrasound is another medical imaging option for performing a VCUG

The sonographer administers a warm gel to the patient’s belly and uses an ultrasound probe to obtain images. 

Specialists use an ultrasound to photograph and monitor the bladder and kidneys as the contrast fills the bladder.

Ultrasounds differ from X-rays in that they do not involve the use of radiation. 

In general, a VCUG procedure should include an evaluation of(6):

  • Urethral morphology
  • Bladder capacity, contour, and emptying capacity
  • The presence and severity of reflux
  • Spine and pelvis

Healthcare professionals must review clinical data and imaging study results before beginning the examination(7).

Radiology specialists may also decide whether the procedure should use catheters(8).

What to Expect

Before the Test

In a survey of Boston Children’s Hospital’s patients, parents compared the discomfort of a VCUG as similar to or better than an immunization(9).

The hospital also lists several events that patients may encounter before the VCUG procedure, such as(10):

  • In the Radiology Department, a radiologist may discuss the steps of the procedure with the patients. A child life specialist may also be present to help with patient care.
  • The staff would request that the child wear a hospital gown.
  • If the child is toilet-trained, the staff may ask them to take a bathroom break before the exam.
  • The staff would lead the parent and the child to the exam room.

During and After the Test

A VCUG may last between 30 to 60 minutes(11).

A specialized room serves as the venue for the examination. Radiologists may use an X-ray or an ultrasound machine to perform a VCUG

During the VCUG, the staff typically allows the parents to accompany their child. A doctor and an ultrasound or X-ray technician may also be present in the exam room.

The technician or doctor may wash between the child’s legs before inserting a small tube called a catheter into the bladder through the urethra‘s small opening, which is where urine comes out. 

The technician usually cleans the urethral area with three to four cotton balls soaked in “brown soap,” an iodine-based cleaning compound, and one cotton ball soaked in water(12).

A urine sample collection comes after the tube is taped in place.

A radio-opaque liquid would then flow from a bottle through a tube and into the catheter to fill the child’s bladder. On X-ray images, this contrast material illuminates the urinary tract(13).

Radiologists may use fluoroscopy, a unique X-ray technique, to obtain images of the child’s bladder filling and emptying. A monitor in the room may display these pictures.

The child usually feels nothing during the imaging procedure. 

However, the child may experience stinging while peeing for the first few times following the test, so extra fluids can be beneficial(14).

Results Interpretation

The radiologist, which is a doctor trained in reading and interpreting X-ray and ultrasound images, reviews the images. The radiologist may send the client a report, which the child’s doctor would read and explain to the parent what the results mean.

Clients may immediately obtain the results of a VCUG in an emergency. Otherwise, results are typically available in 1 to 2 days(15)

Due to the images requiring detailed analysis, in most cases, hospitals do not deliver the results to the family members or the patient at the time of the procedure.

Equipment Used in the Procedure

The VCUG typically employs a radiographic table, one or two X-ray tubes, and a video monitor. Fluoroscopy converts X-rays into video images. 

Doctors use the images to monitor and navigate procedures. An X-ray machine and a detector suspended above the exam table would produce the video.

An additional piece of equipment is the catheter. This tool is a flexible, hollow plastic tube that can fill the bladder with water-soluble contrast material

The catheter is narrower than the urethra.

What is Fluoroscopy?

Fluoroscopy is an imaging method that employs X-rays to produce “real-time” or moving images of the body. Moreover, this procedure aids doctors in understanding how an organ or body system works. 

A radiologist, who is an X-ray doctor, and a radiologic technologist carry out the fluoroscopy procedures.

Specialists must have a good understanding of potential anomalies and irregularities that may occur in the children population and techniques that improve disease visualization. These prerequisites allow the detection of the most common disease states with shallow radiation exposure(16). 

On the other hand, poor technique may lead to excessive radiation exposure and poor disease characterization.

A voiding cystourethrogram cannot assess the obstruction of urine flow from the kidneys. Additional tests may be necessary when there is obstruction.


There are several benefits to employing VCUG

  • After an X-ray exam, no radiation remains in the patient’s body.
  • The test results enable doctors to ascertain whether therapy is necessary.
    Some situations do not require treatment, while others may require it. Meanwhile, some people may even require surgery.
  • In the usual diagnostic range for the exam procedure, the amount of radiation from the X-ray usually has no side effects(17).
  • Voiding cystourethrograms supply helpful and thorough information to help clinicians prevent kidney damage in patients with urinary tract infections.


While VCUG is generally safe, some people are sensitive to the iodine-based dye. This condition is infrequent because the dye enters the bladder rather than the bloodstream(18).

Minor reactions involve:

  • Nausea
  • Vomiting
  • Hot flashes

Antihistamines are usually effective in treating the symptoms above(19).

More adverse reactions include:

  • Swelling of the mouth or throat
  • Cardiac arrest
  • Trouble breathing
  • Low blood pressure

A urinary tract infection is also possible, as with any use of a catheter. The radiation exposure during this test is minimal(20).

The Role of Patients and Guardians During the Test

Patients and guardians can assist their children in preparing for a VCUG by explaining the test using ordinary words.

 If the child is old enough to understand, honesty about the temporary discomfort they may experience is necessary. However, children may also require reassuring words from their parents or guardians.

A mild sedative can make catheter placement easier for toddlers and preschoolers. If sedation can benefit the child, the specialist in charge of the initial assessment may inform the doctor.

Parents or guardians may provide the details about the room and the equipment for the procedure. Moreover, they can also explain to older children the importance of remaining still while a specific device captures images.

Some children require a distraction, like toys, books, and bubbles during the test, while others prefer to observe what is going on. Others may cry and require additional reassurance(21).

How Much Radiation Is Used in the VCUG Test?

The mean effective radiation dose of a VCUG using low-dose fluoroscopy is around three millirems(22)

However, the average effective dose of VCUG may vary according to patient size, operator, and equipment.

During X-ray exams, doctors take special precautions to use the slightest radiation dose while producing the best images for analysis. 

National and international radiology safety organizations are constantly reviewing and updating the technical standards for radiology specialists.

Modern X-ray systems use controlled X-ray beams and dose control methods to reduce stray (scatter) radiation. These features guarantee that the areas of the patient’s body that are not prioritized receive the least amount of radiation exposure.

There is no radiation if the procedure is via ultrasound. Ultrasound is safe, and the FDA has approved the contrast material used in VCUG examinations(23).

How Much Does a VCUG Cost?

One webpage reports that a Cystogram (VCUG) may cost up to $293 to $845(24). However, the cost of the procedure may largely depend on the location and the hospital.

  1. Voiding Cystourethrogram (VCUG)
  2. Voiding Cystourethrogram (VCUG)
  3. Pediatric Voiding Cystourethrogram
  4. Ibid.
  5. Child Life Specialist
  6. Pediatric Voiding Cystourethrography: A Pictorial Guide
  7. Ibid.
  8. Ibid.
  9. Voiding Cystourethrogram (VCUG)
  10. Ibid.
  11. Voiding Cystourethrogram (VCUG)
  12. Voiding Cystourethrogram (VCUG)
  13. Voiding Cystourethrogram (VCUG)
  14. Voiding Cystourethrogram (VCUG)
  15. Ibid.
  16. Pediatric Voiding Cystourethrography: A Pictorial Guide
  17. Pediatric Voiding Cystourethrogram
  18. What is a Voiding Cystourethrogram?
  19. Ibid.
  20. Ibid.
  21. Voiding Cystourethrogram (VCUG)
  22. Radiation Safety and Future Innovative Diagnostic Modalities
  23. Voiding Cystourethrogram (VCUG)
  24. Cystogram (VCUG)


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