Appl. Phys. Lab., Ctr. for Industrial and Medical Ultrasound, Univ. of Washington, 1013 NE 40th St., Seattle, WA 98105.
Lower pole kidney stones have lower rates of clearance after shock wave lithotripsy or ureteroscopy compared to other stone locations. Residual stone fragments, post treatment, often lead to additional morbidity and secondary surgery. We describe the use of acoustic radiation force created by transcutaneous focused ultrasound to manipulate the location of stone fragments within the collecting system in order to facilitate their passage. Artificial and human stones were placed in the lower pole of kidneys of a porcine animal model. An open architecture, software based diagnostic ultrasound system and scanhead were modified to produce roughly 100 μs pulses of up to 16 MPa peak positive pressure in water. Stone motion was observed in real-time with simultaneous imaging through the same scanhead and with fluoroscopy. All stones were seen to move. Stone velocities were on the order of 1 cm/s. Stone displacement distance was up to 3 cm, and operators could generally control the direction of stone movement. No evidence of thermal necrosis or mechanical damage of renal tissue was observed. Thus acoustic radiation force can be used to facilitate lower pole stone fragment clearance.
Written by:
Bailey MR, Cunitz BW, Dunmire B, Wang YN, Lu W, Simon JC, Kaczkowski PJ, Sapozhnikov OA. Are you the author?
Reference: J Acoust Soc Am. 2011 Oct;130(4):2423.
PubMed Abstract
PMID: 21973888
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