Dr Mohit Goel

JR , 14/06/2012

The voiding cystourethrogram is a dynamic test used to demonstrates the lower urinary tract and helps to detect the existence of any vesico-ureteral reflux, bladder pathology and congenital or acquired anomalies of bladder outflow tract. It is performed by passing a catheter through the urethra into the bladder, filling the bladder with contrast material and then taking radiographs while the patient voids.

Indications:

Children: Urinary tract infection– Usually done after some weeks of acute

stage or may be done under antibiotic converge. MCU is indicated after the 1st occurrence of UTI in boys or girls.

voiding difficulties : dysuria ,thin stream dribbling, frequency, urgency ,vesico ureteric reflux, trauma. Baseline study prior to lower UT surgery.

Adults: Trauma to urethra, urethral stricture, urethral diverticula ,UTI,Reflux nephropathy prior to renal transplant of one/both kidneys.

Contrast Media:

Urograffin 60% used which is diluted with normal saline in 1:3.

The estimated volume of contrast medium to be given during the examination is determined mainly by the age of the child except for children less than one year of age in whom it is determined by weight.

Less than one year,

Weight (kg) × 7 = capacity (ml)

Less than two years,

(2 × age in years + 2) × 30 = capacity (ml)

More than two years,

(Age in years/2 + 6) × 30 = capacity (ml)

Filming:Once the contrast is instilled, fluoroscopic

screening is performed to see vesicoureteraicreflux or other abnormalities. Patient is turned oblique to ensure minimal reflux is not over looked. If reflux appears , oblique films are taken. If the bladder appears normal, one film is taken in frontal projection at the end of filling. At the end of voiding a frontal film is taken of entire abdomen including kidney to prevent overlooking the vesicoureteric reflux which is seen only on termination of voiding and may reach upper collecting system.

Adult Male:

The voiding study can be modified by getting the patient to void against resistance by using a penile clamp or compression of distilled part of penis, which enhances visualization of urethra by the artificial distension.

.

This is known as choke cystourethrography

Complications:

UTI,

Adverse reactions may result from absorption of contrast medium by bladder mucosa.

Catheter trauma causing dysuria, frequency hematuria and urinary retention

perforation by the catheter or from over distention

Catheterization of vagina or ectopic ureteral orifice

Radiation effect: MCU is a diagnostic procedure that inevitably exposes gonads to some radiation. It should be kept to a minimum. Careful attention to ensure very short screening periods. Tightly collimated X-ray beam.

Several films are taken when performing a VCUG. The first image is a KUB called the scout film. On this film one can evaluate the spine and pelvis (injury or congenital anomaly such as spinabifida) and the soft tissues (calcifications, foreign bodies, etc.).

Several seconds after the contrast material begins to flow, the minimally filled bladder is imaged in the anteroposterior projection. A ureterocele or bladder tumor that is well seen during early filling may become obscured as more contrast material enters the bladder.

On complete filling ,the bladder should appear smooth and regular and there should be no filling defects. The edges of the bladder image should be smooth.

Images captured during voiding will demonstrate the urethra (strictures or obstruction) and the bladder, and they will document the presence or absence of vesicoureteral reflux Unless there is a voiding film, one cannot determine whether the patient has reflux because reflux may only occur with the pressure generated by voiding.

This film shows a normal male urethra; there is no obstruction. The variation seen in the diameter of the urethra is normal.

Indentation at the urethral sphincter (normal)

• The post-void image may demonstrate reflux (contrast seen in the ureter or kidney) or extravasation of urine from the bladder or urethra (such as from a traumatic rupture).

• No reflux and no residual bladder urine is seen in this normal post-void film.. Normal post-void film

A ureterocele is a congenital abnormality found in the urinary bladder. In this condition the distal ureter balloons at its opening into the bladder, forming a sac-like pouch.

Prenatal diagnosis: Hydroureteronephrosis

A cystic structure in the bladder

Oligohydramnios

On an oblique cystourethrogrmobtained during voiding, the ureterocele is seen to evert and simulate a bladder diverticulum.

.

Oblique voiding

cystourethrogram

demonstrates irregularity

of the bladder base

caused by tumoral

invasion of the bladder lumen .

Bladder sphincter

dyssynergia.

Oblique voiding

cystourethrogram

demonstrates an unusual

urethral caliber and multiple

bladder diverticula due to

bladder contractions against

the incompletely relaxed

external sphincter. These

findings indicate a neurogenic

bladder.

Anterior urethral

stricture.

Oblique voiding

cystourethrogram of

the posterior urethra

poorly depicts a

stricture, which is

seen near the edge of the image .

Posterior urethral valves.

Oblique voiding

cystourethrogram shows a

filling defect in the urethra with

a marked change in urethral

caliber at the level of the

defect, a finding that indicates

obstruction. The secondary

changes crucial to the

diagnosis—trabeculated

bladder, abnormally prominent

bladder neck, and dilated and

elongated posterior urethra—

are clearly depicted .

Meatal stenosis.

Oblique voiding

cystourethrogram

demonstrates marked

dilation of the urethra due

to obstruction at the

narrowed meatus. Note the

abrupt change in the

caliber of the contrast

material stream at the level

of the meatus.

Urachal remnant, posteriorurethral valves, and reflux.

Oblique VCUG demonstratesa large urachal remnantextending from the superioraspect of the small-capacitybladder. Reflux, which isreported in about one-third ofchildren with posterior urethralvalves, is also present .Although the valve is clearlyseen (arrow), the secondarychanges are not welldeveloped due to aberrantmicturition into the urachalremnant and ureter.

On an anteroposteriorvoiding cystourethrogram, the diverticulum is not visualized.

Oblique voiding cystourethrogram demonstrates a posterolateral bladder diverticulum.

Pseudoureterocele.

Anteroposterior voiding cystourethrogram shows a collection of air on the left side producing a filling defect (arrowheads). The air was introduced into the bladder via a catheter. Air can also simulate tumor or blood clots.