The Reliability of Bladder Volume Determination in Children Using Portable Ultrasonographic Scanner in Standing Position

Objective: This study aimed to compare the pre-voiding bladder and post-voiding residual [BV, post-void residual (PVR)] volumes measured by the portable ultrasonic scanner (PUS) in standing and supine positions. Materials and Methods: This study included 436 children. Two groups were composed (group-1: PUS vs. volume by catheter and group-2: PUS vs. infused volume during the urodynamic study) to evaluate the agreement of PUS measurements with true bladder volume. Additionally, the third group (group-3) was created to analyze the correlation between PUS measurements in different positions. In groups 1 and 2, PUS measurement agreements were evaluated using the paired sample T or Wilcoxon signed-rank tests. Following the agreement, correlations were analyzed using Pearson’s or Spearman’s coefficients depending on whether variables were distributed normally or not, respectively. Coefficients were interpreted as 0.90-1.00 (very high correlation) and 0.70-0.90 (high correlation). Results: The catheter and PUS measurements were similar in group-1 (Wilcoxon signed-rank test, p=0.976) and were highly correlated (r=0.873). The measurements of volumes infused by urodynamic device and PUS were similar in group-2 that revealed the agreement of PUS measurements on different volumes and highly correlated at the 25^th and very highly correlated at the 50^th, 75^th, and 100^th percentiles of the estimated bladder capacity related to age. The BV and PVR measurements by PUS in standing and supine positions in group-3 were highly correlated, revealing that PUS can be used in both positions. Conclusion: Measurements of BV before uroflowmetry or PVR volume by PUS in standing position gave similar results with those in the supine position.