Dynamic SPECT evaluation of renal plasma flow using technetium-99m MAG3 in kidney transplant patients.

OBJECTIVE The purpose of this study was to evaluate Patlak's graphic analysis method to determine renal plasma flow (RPF) in kidney transplants. METHODS Dynamic SPECT was performed with 99mTc MAG3 in 12 patients. RPF was determined by both Patlak's graphic analysis method and Russell's method. Ventral, central and dorsal tomographic images of the transplanted kidney were reconstructed to estimate intrarenal distribution of renal plasma flow. RESULTS The renal influx constant (Ku) calculated by Patlak's graphic analysis method was reproducible and correlated with both serum creatinine (r = -0.88, P < 0.001) and blood urea nitorogen levels (r = -0.82, P < 0.002). However, a significant difference was noted between the RPF values derived from Patlak's graphic analysis method and Russell's method. Ku was corrected by a factor calculated from raw and reconstructed data, and the resulting values were in fair agreement with those determined by Russell's method. CONCLUSION These methods are useful in evaluating the function of transplanted kidneys.