Abstract
VCU offers a comprehensive evaluation of the lower urinary tract by combining both anatomical and functional assessments.
7.1 Introduction
Videocystourethrography (VCU), also known as videourodynamics, comprises synchronous radiological screening of the urinary tract during subtracted dual-channel filling and voiding cystometry [1].
VCU offers a comprehensive evaluation of the lower urinary tract by combining both anatomical and functional assessments.
7.2 Technical Requirements for VCU
The equipment for dual-channel subtracted cystometry during VCU is identical to that for conventional cystometry described in Chapters 4 and 5. In addition, special equipment – which includes a radio-opaque filling medium and facilities for imaging of the urinary tract – is required. VCU is usually performed within a fluoroscopy unit with a high-resolution image intensifier and a tilt table designed for urodynamics so that the patient can be moved from supine to upright positions during provocative testing and when voiding (Figure 7.1). The professional undertaking VCU should also have completed ionising radiation protection training.
Figure 7.1 Fluoroscopy unit with a high-resolution image intensifier and a tilt table
7.3 Conducting VCU
The equipment for subtracted dual-channel cystometry should be set up as described in Chapter 4. Uroflowmetry, insertion of catheters and measurement of residual urine are undertaken in the supine position similar to conventional urodynamics. A nonionic, low osmolality, iodinated contrast medium like iohexol (Omnipaque 140, GE Healthcare) is used to fill the bladder instead of physiological (0.9%) saline. X-ray screening is undertaken as screen shots at intervals during the test rather than continuously, to minimise the patient’s exposure to ionising radiation. Most units have a radiographer to perform screening under instruction by the urodynamicist. It would be usual to take images during filling when a patient complains of leakage, at rest in standing position, on provocation during coughs or running taps, during voiding and on completion of voiding. A patient may be asked to interrupt the flow after normal flow is established to allow measurement of piso or isovolumetric detrusor pressure and to facilitate visualisation of vesicoureteric reflux during simultaneous imaging of the urinary tract.
7.4 Observations during VCU
Real-time imaging of the urinary tract at appropriate stages of filling and voiding cystometry can provide useful additional information to be acquired at each step of the procedure.
1. Imaging during filling cystometry: Full bladder at rest – allows morphological assessment of bladder, presence of trabeculations, diverticula, vesicoureteric reflux and any pelvic masses indenting the bladder.
2. Imaging during straining or coughing: Presence and severity of incontinence (in the authors’ practice, leaking with the first cough is graded as severe incontinence, leaking during a series of three coughs as moderate leakage and leakage occurring only at the end of five coughs as mild incontinence), evidence of pelvic organ prolapse, and/or bladder neck descent and rotation.
3. Imaging during voiding cystometry: Urethral obstruction or narrowing, dilatation and urethral diverticulum can be noted. Imaging during a ‘Stop Test’ assesses the voluntary urethral closure mechanism or pdet iso (peak isometric detrusor pressure). A rise in pressure or pdet iso indicates at least some degree of contractility of the detrusor. It also may be used to demonstrate the presence and severity of vesicoureteric reflux. Vesicoureteric reflux can be graded according to the height of reflux up the ureters and degree of dilatation of the ureters: Grade 1 – limited to the ureter, Grade 2 – reflux up the renal pelvis and calyces, Grade 3 – mild dilatation of the ureter and pelvicalyceal system, Grade 4 – tortuous ureter with moderate dilatation, blunting of fornices but preserved papillary impressions, Grade 5 – severe dilatation of the fornices and pelvicalyceal system, loss of papillary impressions [2]. Each side may have a different grade of reflux.
4. Imaging on completion of voiding: It is used to check for residual urine.
Imaging is especially helpful in neurogenic patients who may show severe bladder trabeculations with diverticula and pseudodiverticula, wide bladder neck and proximal urethra (Figure 7.2) and vesicoureteric reflux. Patients with Parkinson’s disease and Multiple sclerosis may show evidence of detrusor-external sphincter dyssynergia [3].
