Effects of lithotripsy on rat kidney: evaluation with MR imaging, histology, and electron microscopy

Magnetic resonance (MR) imaging at 1.5 T was used to evaluate the effects of extracorporeal shock wave lithotripsy (ESWL) in 30 rats and the findings on T1- and T2-weighted (spin echo 600/22, 1,600-2,000/90) images were compared with histology and scanning microscopy. The observed pathologic changes increased in severity with the number of shock waves given (500-5,000 15 kV). Post-ESWL MR findings in 54 kidneys included perirenal and subcapsular fluid (n = 30), diffuse loss of corticomedullary junction definition (n = 28), intrarenal foci of increased (n = 7) or decreased (n = 6) signal intensity, focal indentation of the renal contour (n = 5), and loss of distinction between the renal, splenic, or hepatic contour (n = 7). The subcapsular and intrarenal findings corresponded pathologically to areas of hemorrhage and hematoma formation--the contour changes to foci of renal scarring or perirenal adhesions. Electron microscopy demonstrated marked alterations of the renal tubules and vasculature. The study shows the feasibility of assessing the nature and chronology of renal damage post-ESWL in a rat model by MR.