Fresco G F, DiGiorgio F, Curti G L
Department of Internal Medicine, University of Genoa Medical School, Italy.
J Nucl Med. 1995 Sep;36(9):1701-6.
Comparing the measurements of both glomerular filtration (GFR) and tubular excretion rates [TER(MAG3)] by multi-sample and single-sample methods has been performed after a single bolus injection of 3.7 MBq 51Cr-EDTA plus 37 MBq 99mTc-MAG3.
We studied 17 healthy volunteers and 28 patients with a wide range of renal function. For each plasma clearence curve, nine plasma samples were drawn at intervals from 10 to 240 min after injection of tracers. When comparing individual values for GFR and TER (MAG3) from the tracer dilution spaces (VD) with those derived from the analysis of the entire plasma disappearance curves of two radiopharmaceuticals, a good linear correlation appears (r = 0.96).
We found that the nadir-error (Sy,x) for predicted GFR occurs at 180 min (11.0 ml/min/1.73 m2), while the nadir-error for predicted TER (MAG3) is reached at 90 min (26.4 ml/min/1.73 m2).
In the computation of GFR and TER (MAG3) with a single-sample method, it appears that the mean residence time (t) for each tracer represents the optimum plasma sampling time. Our results suggest that the single injection of 51Cr-EDTA and 99mTc-MAG3 followed by blood sampling twice permits accurate simultaneous estimation of GFR and TER (MAG3) and, after correction of the latter kinetic parameter, effective renal plasma flow.
在单次静脉注射3.7 MBq 51Cr - 乙二胺四乙酸（EDTA）加37 MBq 99mTc - 巯基乙酰三甘氨酸（MAG3）后，已采用多样本和单样本方法比较肾小球滤过率（GFR）和肾小管排泄率[TER（MAG3）]的测量值。
我们研究了17名健康志愿者和28名肾功能范围广泛的患者。对于每条血浆清除曲线，在注射示踪剂后10至240分钟间隔抽取9份血浆样本。当比较来自示踪剂稀释空间（VD）的GFR和TER（MAG3）的个体值与通过分析两种放射性药物的整个血浆消失曲线得出的值时，出现良好的线性相关性（r = 0.96）。
我们发现预测GFR的最低点误差（Sy,x）出现在180分钟（11.0毫升/分钟/1.73平方米），而预测TER（MAG3）的最低点误差在90分钟时达到（26.4毫升/分钟/1.73平方米）。
在采用单样本方法计算GFR和TER（MAG3）时，似乎每种示踪剂的平均停留时间（t）代表最佳血浆采样时间。我们的结果表明，单次注射51Cr - EDTA和99mTc - MAG3后进行两次血液采样可准确同时估算GFR和TER（MAG3），并且在对后一动力学参数进行校正后可估算有效肾血浆流量。
