Experimental evaluation of furosemide renography in unobstructed and partially obstructed upper urinary tracts in pigs.

To evaluate the reliability and the constancy of the furosemide renography an experimental evaluation of the test has been performed. A standardized unilateral partial proximal ureteral obstruction was applied to 11 pigs. Preoperatively and again weekly in the three weeks following obstruction a furosemide renogram (FR) was done. The furosemide renography was a very constant parameter in the unobstructed kidney (85%) and in the partly obstructed kidney (85%). A type I FR pattern (O'Reilly classification) was an exact indicator of an unobstructed pelvis. After partial ureteral obstruction, an immediate change in the FR pattern was seen either into type II or type IIIa renography. In this experimental study furosemide renography was found to be a reliable tool in the differentiation between the unobstructed normal renal pelves and the partly obstructed dilated renal pelves.