TC-99(M)-MAG3 - A SENSITIVE INDICATOR FOR EVALUATING PERFUSION AND REJECTION OF RENAL-TRANSPLANTS

Radionuclide renography has a role in evaluating perfusion of transpla nted kidneys. In the course of rejection, cortical perfusion decreases before urinary excretion changes. Based on the facts that Tc-99(m)-MA G3 has different pharmacokinetics and shows a higher kidney-to-backgro und count ratio than Tc-99(m)-DTPA, we postulated that Tc-99(m)-MAG3 w as a sensitive and reproducible agent to measure cortical perfusion of transplanted kidneys. To clarify the feasibility of using Tc-99(m)-MA G3 to measure the cortical perfusion index (CPI), sequential renograph y was performed using Tc-99(m)-DTPA and Tc-99(m)-MAG3 in 14 patients w ith stable renal transplants, who had changes in serum creatinine conc entration of less than 50% between the two studies. The CPI was calcul ated with Tc-99(m)-DTPA and Tc-99(m)-MAG3 and these were then compared and correlated with concurrent serum creatinine concentration. The CP I with Tc-99(m)-MAG3 was 1.43 times that with Tc-99(m)-DTPA in patient s with changes in serum creatinine concentration equal to or less than 20%, and regression analysis revealed that the difference in CPI was larger in patients with more severely decreased renal perfusion than i n patients with normal or mildly decreased renal perfusion. This preli minary study has indicated that the CPI with Tc-99(m)-MAG3 is a sensit ive index for detecting changes in renal function, and thus is a feasi ble indicator of cortical perfusion when evaluating the rejection of t ransplanted kidneys.