Time-lapse nondestructive assessment of shock wave damage to kidney stones in vitro using micro-computed tomography

To better understand how lithotripter shock waves break kidney stones, we treated human calcium oxalate monohydrate (COM) kidney stones with shock waves from an electrohydraulic lithotripter and tracked the fragmentation of the stones using micro-computed tomography (mu CT). A desktop mu CT scanning system, with a nominal resolution of 17 mum, was used to record scans of stones at 50-shock wave intervals. Each ACT scan yielded a complete three-dimensional map of the internal structure of the kidney stone. The data were processed to produce either two- or three-dimensional time-lapse images that showed the progression of damage inside the stone and at the surface of the stone. The high quality and excellent resolution of these images made it possible to detect separate patterns of damage suggestive of failure by cavitation and by spall. Nondestructive assessment by mu CT holds promise as a means to determine the mechanisms of stone fragmentation in SWL in vitro. (C) 2001 Acoustical Society of America.