Computerized scintigraphy using " Tc-DTPA was performed to 37 isolated rabbit kidneys after preservation for 48 hours in perfusates differing in their compositions, i. e., Group 1 (N 9) in Collins solution, Group 2 (N 10) in Collins' plus trifluoperazine, Group 3 (N 9) in Collins plus urokinase and Group 4 (N 9) in Collins plus urokinase pJus verapamil. Satisfactory images, and statistically analyzable quantitative indices such as perfusion score, filtration rate and cortical uptake rat.io (CUR) were obtained by the evaluations of first-pass perfusion, equilibration slopes and postequilibration images. Significant improvements in CUR were observed by adding trifluoperazine (Group 2) and urokinase (group 3) as compared to Collins only group (Group 1), p(0.05 for each, and aIl of the three indices