Pediatric Radiology > Genitorinary > Voiding Cystourethrogram > The Evaluation of Vesicoureteral Reflux

The Evaluation of Vesicoureteral Reflux

The voiding cystourethrogram (VCUG) is utilized in the detection and grading of vesicoureteral reflux. The VCUG is performed after the diagnosis of a urinary tract infection. Sedation is usually not necessary and can make the study more difficult by inhibiting the voiding reflex. The exam is performed in the radiology fluoroscopy suite, preferably with the ability to record the exam on videotape, as the reflux can be transitory.

A urinary bladder catheter should be placed under sterile conditions. A balloon should not be used as the balloon may inhibit visualization of ureteroceles and may alter voiding. At our institution we use a 5 french pediatric feeding tube in the infant/ toddler population and an 8 french pediatric feeding tube in the older population.

Sterile urine collection or post void measurement may be requested by the referring urologist.

Because of the radiation to the pelvic region, strict attention must be made to the fluoroscopic technique following the principle of "as low as reasonable" (ALAR) radiation exposure. Most uncomplicated exams should involve less than 10 seconds of fluoroscopy time.

We use 30% hypaque, a dilute ionic contrast agent, to visualize the urinary tract. The bladder is filled by gravity at a height of approximately 2-3 feet above the table.

Bladder capacity can be estimated by:
(Patient age + 2) * 30.

This works out to be...
Newborn: 15 cc
One yr old: 90 cc
Two yrs old: 120 cc
Three yrs old: 150 cc
Four yrs old: 180 cc
Five yrs old: 210 cc


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