Around 40% of infants affected by PUV have abnormal bladder capacity and almost half of them have significant post void residuals following primary resection. Although controversies and limitations are present, we believe that this non-invasive study can provide valuable information to understand the dynamic of the bladder, particularly in children affected by PUV and allow early intervention in children considered "at risk". Having a non invasive way of assessing can help tailor intervention and be useful for future research into early bladder intervention and improving outcomes.