Selective release of CO2-loaded nanoparticles for vesicoureteral reflux imaging

Vesicoureteral reflux (VUR) is a disorder affecting young children in which urine flows backwards from the bladder to the kidneys. This can have serious health consequences in children and thus it is important to diagnose VUR reliably. However, the current diagnostic tests involve physically and emotionally traumatizing catheterization of children to inject radiographically detectable contrast agents. We propose an ultrasound-based technique in which CO
2
-loaded nanoparticles are injected intravenously and undetectable until targeted by ultrasound in the bladder to produce CO
2
bubbles. These bubbles can then be visualized with standard B mode imaging to determine flow direction, and thus detect VUR. This strategy allows the nanoparticles to be excreted by the kidneys and, if successful, eliminates the need for catheterization and radiation exposure.