Voiding cystourethrography (VCUG), also known as a micturating cystourethrography (MCU), is a fluoroscopic study of the lower urinary tract in which contrast is introduced into the bladder via a catheter. The purpose of the examination is to assess the bladder, urethra, postoperative anatomy and micturition in order to determine the presence or absence of bladder and urethral abnormalities, including vesicoureteral reflux (VUR).
It is more commonly performed in the paediatric population than adults.
As per American College of Radiology (ACR) and Society for Paediatric Radiology (SPR) guidelines clinical indications for voiding cystourethrography include, but are not limited to:
- urinary tract infection
- dysfunctional voiding
- hydronephrosis and/or hydroureter
- bladder outlet obstruction
- neurogenic dysfunction of the bladder, e.g. spinal dysraphism
- congenital anomalies of the genitourinary tract
- postoperative evaluation of the urinary tract
Fever ≥39°C (102.2°F) and a pathogen other than E. coli after a first febrile urinary tract infection in a child is also considered a strong indication due to an increased risk of renal scarring in this population 2.
- the bladder is filled with contrast using an infant feeding tube under aseptic precautions; a Foley catheter can be used for older children
- intermittent screening of the patient on fluoroscopy, while distending the bladder with contrast, is necessary to check for a ureterocoele or VUR
- after the bladder is filled to its capacity (which will vary as per age of patient) the patient is now asked to void
The following projections should be acquired keeping within the ALARA principle:
- AP with full bladder for demonstration of the presence or absence of VUR.
- both obliques to demonstrate bilateral vesicoureteric junctions.
- post void film to check for a ureterocoele.
VCUG/MCU vs RUG/ASU
While the urethra is well outlined in both procedures RUG/ASU is better to visualise anterior urethral abnormalities and VCUF is better for posterior urethral abnormalities. Additionally VCUG is carried for detection of bladder abnormalities and vesico-ureteric reflux (VUR).
- 1. Jequier S, Jequier JC. Reliability of voiding cystourethrography to detect reflux. AJR Am J Roentgenol. 1989;153 (4): 807-10. doi:10.2214/ajr.153.4.807 - Pubmed citation
- 2. Shaikh N, Craig JC, Rovers MM et-al. Identification of children and adolescents at risk for renal scarring after a first urinary tract infection: a meta-analysis with individual patient data. JAMA Pediatr. 2014;168 (10): 893-900. doi:10.1001/jamapediatrics.2014.637 - Pubmed citation