Comparative Study Between 99 mTc - MDP and 99 mTc - DTPA as a Predictor For Renal Function

Renal scintigraphy can provide the valuable split renal function which is not obtainable by other non-invasive measurements. This study was designed to investigate the feasibility of the assessment of relative renal function with Tc-MDP as compared with renal imaging radiotracers used for that purpose. Differential renal functioni.e the contribution of percent that each kidney makes to global renal function was determined prospectively in35 patients (23 males, 12 females, mean age 47± 14y) usingTc-MDP and a renal radionuclide tracer Tc-DTPA. Differential function was computed in all cases from the early (1-3 minutes) renal uptake of the tracers by Region Of Interest analysis (ROI)of the computer acquired data. There was a high correlation between values of differential renal function obtained with Tc-MDPand those obtained with Tc-DTPA (r= 0.98, P<0.0001). Total glomerular filtration rate, split glomerular filtration rate and renograms time to peak activity derived from both tracers were also highly correlated (r=0.96, P<0.0001), (r= 0.98, P<0.0001)and (r= 0.97, P<0.0001), respectively. It is concluded that the characteristics of renal handling ofTc-MDP were similar to those ofTc-DTPA so that accurate estimation of differential renal function are possible with this agent, and that Tc-MDP determined renal function most likely reflects differential glomerular filtration rate.