Videoflow: Uroflowmetry in Children Exploiting Standard Care Video Urodynamic Imaging

Pressure-flow study, consisting of flow rate combined with detrusor pressure, is the gold standard to determine bladder outflow obstruction and evaluate the detrusor voiding contraction. In very young children, not able to sit on a uroflowmetry device, the flow rate cannot be measured. This results in an incomplete evaluation of bladder and urethral functions. The aim of this study is to derive the flow rate using standard care video-urodynamic study X-ray images.

We retrospectively included 50 video urodynamic studies in children able to void on a uroflowmetry toilet, to correlate the outcome with standard uroflowmetry. The X-ray images taken during voiding were manually segmented and algorithmically converted into a flow rate, called "videoflow". This videoflow was compared with the measured (standard) uroflowmetry.

An excellent cross-correlation of 0.98 was found between the videoflow and normal uroflowmetry outcomes. The videoflow maximum flow rate (Q_max) was accurate with a not significant bias of +0.1 mL/s difference with standard uroflowmetry.

In conclusion, the proposed videoflow is found feasible and accurate in children who are able to void in a uroflowmetry toilet. This method paves the way to measure urine flow rate in very young children who cannot yet sit upright. For the first time, this new technique will enable the validation of a pressure-flow-based urethral resistance measurement in this very young age group.

Clinical Registration Number: 23U-0621.