QUANTITATION OF SHOCK-WAVE LITHOTRIPSY-INDUCED LESION IN SMALL AND LARGE PIG KIDNEYS

Background Shock wave lithotripsy (SWL) is known to cause injury to th e kidney, However, it is not known how lesion size varies as the param eters of SWL treatment (number of shocks, kilovoltage, kidney size) ar e changed, This hypothesis could not be tested because there was no me thod available to quantitate accurately the SWL-induced renal lesion, Methods: A dosage of 2,000 shocks at 24 kV delivered by an unmodified Hornier HM3 lithotripter was applied to the lower pole calyx of the ri ght kidney of small and large pig kidneys. A new method was developed to embed a whole pig kidney for serially sectioning, recording, and di stization, Automated computer color recognition made it possible to di scriminate regions of hemorrhage from undamaged tissue and allowed qua ntitation of the lesion in single sections and in the entire kidney, R esults: The new protocol resulted in an accurate identification of sit es of hemorrhage and calculations of the volume fraction of injured re nal tissue, Lesion size induced in small kidneys was significantly lar ger than that induced in the larger kidneys (7.6 +/- 1.2% and 1.6 +/- 0.7%, respectively), Conclusions: Computer segmentation of serially se ctioned SWL-treated kidneys has determined that kidney size is a risk factor for enhanced renal injury. (C) 1997 Wiley-Liss, Inc.