A videourodynamics study is essential when anatomic information is needed to corroborate functional (urodynamic) observations. Fluoroscopic images for VUDS are typically obtained with the patient positioned for an anterior-posterior (AP) or lateral image. Positioning is mainly determined by clinical information that is desired, but patient body habitus and mobility limitations also influence positioning. Images necessary to diagnose incontinence, vesicoureteral reflux, and bladder outlet obstruction can usually be obtained with the AP position; however, accurate imaging of urethral abnormalities such as stricture disease is best performed in the lateral position as this affords the best visualization of the urethra.

An initial scout film should be obtained. The main purpose of the scout film is for confirmation of desired patient position. Bony abnormalities are another finding that can be noted prior to initiation of the study. Attention should be paid to the spine when assessing patients with known or suspected neurogenic bladder. Surgical clips or other implants can provide information about prior procedures. Periodically a patient will have had other recent imaging with radiographic contrast. The baseline appearance of this must be noted to prevent misinterpretation of the VUDS findings.

After the bladder is partially filled with radiographic contrast, a resting image is obtained. This image provides additional useful information such as bladder shape and outline, bladder position at rest, bladder neck at rest, and abnormalities such as bladder diverticula (Fig. 1). The bladder outline is often irregular at volumes less than 200 mL because of external compression from adjacent bowel and pelvic organs [11]. If an abnormal finding is suspected to be due to external compression, a repeat resting image should be obtained when the bladder has been filled with more contrast.

Once the resting image is acquired, a strain (Valsalva) or cough image is obtained. During straining, bladder neck competence and any associated incontinence (abdominal leak point pressure), degree of bladder descent (cystocele), and presence of vesicoureteral reflux can be assessed (Figs. 1 and 2).

When the bladder is filled to capacity, a voiding cystourethrogram (VCUG) is performed. This portion of the VUDS is key when evaluating a patient for obstruction or when there is concern for high-pressure voiding causing reflux. During this phase appropriate bladder neck and external sphincter relaxation and the urethral outline are observed. The presence of vesicoureteral reflux is again assessed. If stricture disease or other urethral pathology is suspected, the VCUG is best performed with the patient positioned such that a lateral image is obtained (Fig. 3a). If the VCUG is performed in the sitting position, a radiolucent chair is necessary. Female patients generally find it easier to void in a seated position, but if a woman is expected to void while standing then a funnel device is necessary.

Finally, a post-void image is obtained to determine bladder emptying (Fig. 3b). This image may be omitted to reduce radiation exposure if the post-void residual can be accurately determined based on volume of contrast instilled and volume voided or when the post-void residual is not a concern. The post-void image can also be useful to determine how much fluid is retained in a diverticulum after voiding.

Figure 4 shows the imaging sequence for VUDS.

Patients with symptoms of mild stress incontinence that is not demonstrated by physical examination can have their diagnosis confirmed with a VUDS. Even the smallest amount of incontinence can be detected with fluoroscopy. On the contrary, the diagnosis of stress incontinence must be questioned when a patient’s resting and straining images fail to demonstrate an open bladder neck. Studies have shown that presence of an open bladder neck correlates strongly with the presence of stress urinary incontinence [12]. In this study, none of the continent patients had an open bladder neck during a VUDS implying that a closed bladder neck should raise the suspicion that the patient has a diagnosis other than stress urinary incontinence.

In addition to providing information regarding the presence of incontinence, fluoroscopy also provides information as to the severity of incontinence. With a VUDS the amount of incontinence can be visually quantified and correlated with abdominal leak point pressure. This becomes relevant when a patient is presented with treatment options. A patient with incontinence of only a few drops of urine at a very high Valsalva leak point pressure (VLPP) may be an appropriate candidate for a bulking agent. On the other hand, a patient with a completely incompetent bladder neck who leaks with a minimal increase in abdominal pressure needs to consider closure of the bladder neck.