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Noninvasive ureterocele puncture using pulsed focused ultrasound: an in vitro study.

PURPOSE
To evaluate the feasibility of performing noninvasive puncture of pediatric ureteroceles with cavitation-based focused ultrasound (US) (histotripsy).


MATERIALS AND METHODS
A model for the ureterocele wall was developed from an excised bovine bladder wall. The model was exposed to focused US pulses in a water bath under three different US parameter sets for up to 300 seconds to create localized perforations in the wall. B-mode US imaging was used to monitor the treatment and assess potential imaging guidance and feedback.


RESULTS
Punctures were formed between 46-300 seconds, depending on the focused US exposure parameters and model wall thickness. Puncture diameter was controllable through choice of exposure parameters and could be varied between 0.8-2.8 mm mean diameter. US-induced cavitation was visible on B-mode imaging, which provided targeting and treatment feedback.


CONCLUSIONS
Cavitation-based focused US can create punctures in a model that mimics the tissue properties of a ureterocele wall, under guidance from US imaging.