Videourodynamics is a functional test of the lower urinary tract in which filling cystometry and pressure-flow studies are combined with real-time imaging of the lower urinary tract, mostly in the form of fluoroscopy. Radiation exposure during videourodynamic studies (VUDS) is a concern for patients undergoing VUDS. Clinicians should inform patients about the radiation risk associated with VUDS; however there is limited data on the specific factors that are associated with an increased risk of radiation exposure in adults. We aimed to systematically evaluate the radiation exposure during videourodynamic (VUD) studies and to comprehensively identify clinical and urodynamic parameters associated with increased fluoroscopy time.

This retrospective chart review study analyzed clinical and urodynamic data from 469 consecutive patients who underwent VUD at a tertiary referral center. The ICS Good Urodynamics Practice Guidelines were followed for each procedure. The data on fluoroscopy time was recorded prospectively, as it was a mandatory component of the urodynamics report. Data collected included demographic information (age, gender, body mass index [BMI]), bladder capacity determined by uroflowmetry, post-void residual (PVR) volume, maximum urinary flow rate (Qmax), surgical history, presence of pre-VUD incontinence, neurological diseases, and documented voiding dysfunction. Fluoroscopy time was recorded during each VUD procedure as a direct measure of radiation exposure. Statistical analyses included univariate and multivariate evaluations to identify correlations between these clinical factors and prolonged fluoroscopy durations.

The cohort comprised 68.7% females, with a mean age of 50,25 years. Indications for VUD investigations were neurogenic bladder 103 patients (22%), mixed urinary incontinence 51 patients (10,9%), refractory OAB 110 patients (%23,5), female voiding dysfunction 13 patients (2,7%). The  overall mean fluoroscopy time was 62.03±35.90 seconds. We did not identify any pre-urodynamic parameters such as BMI, age, gender, neurological disease, incontinence, or voiding symptoms that were associated with an increased risk of fluoroscopy time (Table-1). Among the urodynamic parameters, bladder outlet obstruction (BOO), vesicoureteral reflux (VUR) and urinary incontinence were associated with an increased fluoroscopy time compared to patients without these conditions (Table-2). Also, male patients with detrusor overactivity (DOA) had significantly longer fluoroscopy durations compared to those without DOA (69.67±42.71 seconds vs. 54.70±28.48 seconds, p=0.012).

We did not identify any clinical parameters that can predict an increased risk of radiation exposure during VUD. However, presence of BOO, VUR and incontinence during the VUD test was associated with an increased radiation exposure. The prolonged fluoroscopy times in VUR cases likely reflect the necessity for a thorough assessment of upper urinary tract anatomy and reflux severity. Additionally, BOO assessment often requires precise anatomical delineation and functional analysis of the bladder outlet, explaining prolonged imaging durations. This information in a mixed group of patients can be useful to inform patients undergoing VUD studies.

Radiation exposure during VUD procedures may be increased in patients diagnosed with vesicoureteral reflux, bladder outlet obstruction, and urodynamic incontinence, emphasizing the necessity for cautious evaluation and individualized imaging protocols in these populations. Awareness of these risk factors allows clinicians to better anticipate and mitigate radiation exposure risks by employing standardized fluoroscopic techniques, minimizing unnecessary imaging, and optimizing patient selection criteria. Future prospective studies are warranted to validate these findings and to further develop evidence-based guidelines to ensure that radiation exposure during videourodynamic studies remains within the principles of radiation safety and patient-centered care.

Rosier PFWM, Schaefer W, Lose G, Goldman HB, Guralnick M, Eustice S, Dickinson T, Hashim H. International Continence Society Good Urodynamic Practices and Terms 2016: Urodynamics, uroflowmetry, cystometry, and pressure-flow study. Neurourol Urodyn. 2017 Jun;36(5):1243-1260. doi: 10.1002/nau.23124. Epub 2016 Dec 5. PMID: 27917521.