Intrarenal backflow during retrograde pyelography with graded intrapelvic pressure. A pathoanatomic study.

Histologic examination was performed in 21 baby-pig kidneys after retrograde pyelography with a mixture of meglumine sodium diatrizoate and Ferritin at intrapelvic pressures of either 30-35 or 70-75 mm Hg. In further 4 kidneys light microscopy was done after retrograde pyelography with a mixture of barium sulfate and gelatin at an intrapelvic pressure of 70-75 mm Hg. The primary pathway for intrarenal backflow was canalicular. The contrast material entered the interstitium only by one route: Tubular leakage. Only in the central portions of the kidney leakage was seen. Interstitial Ferritin was found more frequently in areas with intrarenal backflow at an intrapelvic pressure of 70-75 mm Hg than of 30-35 mm Hg.