Poster Session 7: Stones and Reconstruction| Volume 8, ISSUE 8, P605, September 2009

N105 Evaluation of renal function following extracorporeal shock wave lithotripsy (ESWL): The use of parametric clearance kidney scintigrams

      Introduction and Objectives

      Extracorporeal shock wave lithotripsy (ESWL) has gained a widespread acceptance due to its effectiveness and noninvasiveness. However, the safety of ESWL has been debated in recent years. Reports of renal parenchymal damage in treated kidneys in animal model suggest local contusions occurring in a remarkable number of treated kidneys. The aim of the prospective study was to evaluate the effect of ESWL on renal function using parametric clearance kidney scintigrams.

      Material and Methods

      A total of 41 patients with untreated, single renal stone the size of 10–20 mm and no hydronephrosis on ultrasound and intravenous pyelography were evaluated before, 7 days after and one month after ESWL with renoscintigraphy. To asseess the effect of ESWL on renal function, 99 mTc-EC parametric clearance image findings and differential renal function parameters at presentation and followup were reviewed. Parametric clearane kidney imaging is a method of functional imaging of the kidney clearance that was elaborated in Nuclear Medicine Deparment of Medical University in Lodz, based on the Patlak-Rutland theory. The intensity of a colour in such obtained images is proportional to the local clearance value.


      See the figure. Analysis of parametric clearance kidney images revealed local parenchymal defects in 16 patients (39%) 7 days after ESWL. These changes resolved in 14 (34%) cases at one month follow-up. The other two patiants had an additional renoscintigraphy performed three months after ESWL that showed no disturbances in the distribution of renal clearance in the treated kidney. There were no statistically significant differences observed between renoscintigraphic parameters describing the function of the whole organ before and after ESWL. The figure shows parametric renal clearance images obtained before and 7 days after ESWL of a calculus located in the lower calyx of left kidney.
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      Extracorporeal shock wave lithotripsy may cause a transient reduction of regional function of the treated kidney