Studies on quantitative analysis of 131I-hippuran renogram. II. Analysis of 131I-hippuran renogram by analog computer simulation

摘要

I. Analog computer simulation The simulation was c onstructed through equations (1) to (5) using the analog computer with a special correction of the initial portion of the distribution space (Fig. 1). Time decaying extraction ratio of 131I-Hippuran, confirmed experimentally (Part I), was taken into consideration in the circuit (Fig. 1). When there are good agreeme n ts between the observed renogram records and the obtained computer results (equation (4)) on a recorder, and concurrently, between the observed excre• tion (%) in urine specimen and the obtained computer results (equation (3)), the individual renal plasma flow rates and other excretory functions can be read from the setting values of potentiometers in the simulator. In Fig. 15 are shown the obtained computer results superposed on the observed RI-renogram records and the concurrently obtained excretion curves which gives a close value to the observed excretion (%) in 20 minutes when potentiometers in the simulator are set at those RPF values shown in Fig. 1. II. The urinary excretion rate of 131IH ippuran. 1) Eff. RPF (CpAEE) was measured b y the standard renal clearance method with 20 urological patients excluding upper urinary obstruction or hydronephrosis. Immediately after this procedure, 20 pc of 131I-Hippuran was injected i. v. to each patient to measure its urinary excretion rates in 10, 15, 20, 25, 30, 35, 40 minutes. 2) The results are shown in Table 1. 3) CpAg and the excretion rate of 1 31I-Hippuran gave a remarkably good agreement as Table 2 shows, i. e. 15 min. (r=0.934), 20 min. (r=0.929), 25 min. 25 min. (r=0.925).... 4) The urinary excretion rate in 17 normal subjects turned out to be 6 6 .7±5.7%. 5) The correlation between Cp.Ag (eff. RPF) and the urinary excre t ion rate was considered in the simulation of RI-renogram record. III. Comparison of individual RPF o btained by split renal function test and individual RPF analysed by analog computer simulation 1180 中川:RI-Renogramの定量的分析に関する研究第II編 1) As is shown in Fig. 16 and Fig. 17, the split renal function test was performed with 19 patients by the unilateral ureteral catheterization technique to compare the individual eff. RPF (CpAH) before the addition of ADH, with the indirect measurement of the individual RPF interpreted by the analog computer simulation of RI-renogram (Table 3). 2) The above mentioned comparison gave a nicely correlated wore to better ratio of RPF (r=0.94). (Fig. 24) The values o f individual RPF showed a relatively low correlation (r=0.86), which is thought to be attributed to the differences of patient's conditions during the RI-renography and the split renal function test (e. g. position, anesthesia, date, urine flow rate, etc.). 3) It was confirmed that the so called background of RI-renogram m e asured by using RISA nicely agrees with the background estimated by the analog simulator (Fig. 25-29) and 131i n equation (5) was thought to be 0.05-0.2. 4) These studies using the renogra m simulator showed that, with the known RI-renogram curves and urinary excretion rate, the RPF in each kidney can be estimated with accuracy comparable to that of conventional troublesome renal clearance procedures.