Technetium 99m pertechnetate measurement of renal blood flow distribution.

The accuracy of measuring anatomical blood flow using the rising slopes of first-pass time-activity curves were studied in six isolated dog kidneys. In each case, the canine kidney was placed on an open-circuit in vitro perfusion apparatus, which included an in-line flow meter and an in-line variable resistance for adjusting the flow rate. Time-activity curves from images acquired at 2-second intervals were generated for each kidney following injection of 4 mCi of 99mTc pertechnetate into the perfusate solution for each flow rate condition studied. The flow rate was calculated from the average slope of the ascending segment, initial rise to peak, of the time-activity curves. Excellent agreement was found between the radioactive tracer and established flow meter measurements (r = 0.995). With the availability of mobile gamma camera/computer systems, this technique could easily be utilized in evaluating perfusion function of transplant kidneys prior to surgery. Also, this technique can be useful in monitoring the renal anatomical distribution of blood flow in postsurgical patients.