Quantitative measurements of renal perfusion following transplant surgery

The authors developed and used the following mathematical model for quantitative perfusion measurement in transplanted kidneys: Rrho = [K(t) X V]/[integral (0,t+T)[A(T)dt], where Rrho = renal perfusion, K = Tc-99m DTPA activity in the kidney, V = ultrasonographically measured femoral artery segment volume, t = time after injection, T = arterial transit time, and A = Tc-99m DTPA activity in femoral artery segment. Preliminary results showed that immediate postsurgical values average 500 ml/minute. Postsurgical acute tubular necrosis caused decreases in perfusion averaging 40%, while injection caused larger decreases, up to 70%