Quantification of renal haemodynamics with radionuclides.
ABSTRACT Non-invasive quantification of renal function with radionuclides is an important role of nuclear medicine. With modern commercial preparations of technetium-99m diethylene triamine penta-acetic acid (DTPA), glomerular filtration rate (GFR) can be measured accurately either from the rate of disappearance of the tracer from plasma or from its rate of uptake into the kidneys. Determination of the latter with the gamma camera allows measurement of individual kidney GFR. Renal blood flow (RBF) can be measured from plasma clearance of hippurate or from first-pass kinetics of intravenously injected tracer using the gamma camera. The filtration fraction can be obtained from separate measurement of GFR and RBF, either globally from plasma clearance studies or of each kidney from gamma camera studies. Because they are central to the understanding of plasma clearance studies, the effective distribution volumes of the various tracers used for renal function studies are also discussed in detail.
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ABSTRACT: The reliability of different clearance methods to assess the glomerular filtration rate (GFR) was tested in fifteen patients with advanced chronic renal failure (range of GFR: 3-13 ml/min). The renal [51Cr]EDTA plasma clearance (Er) measured during optimal conditions with determination of residual bladder-urine was used as reference parameter of GFR and the reliability (+/-) of a thus corrected value to assess GFR of the individual patient are given in parenthesis. The arithmetic mean of the renal plasma clearance of endogenous creatinine (Clcreat) and urea (2.0 ml/min; +/- 1.5 ml/min); single determination of 25-h clcreat (3.4 ml/min; +/- 2.0 ml/min); Clcreat calculated from a measured plasma creatinine concentration, considering sex, age and body weight of the patient (2.9 ml/min; +/- 2.3 ml/min); total [51Cr]EDTA plasma clearance (Et) determined form three blood samples drawn 3-5 h after i.v. single injection 93.7 ml/min; +/- 2.2 ml/min); and Et determined form two blood samples drawn 4 and 24 h after i.v. injection (0.5 ml/min; +/- 0.5 ml/min). It is concluded that the most reliable assessment of GFR (=Er) is achieved either form a direct measurement or indirectly from Et determined from two blood samples drawn 5 and 24 h after i.v. single injection. use of the mean value of three 25-h Clcreat determinations is recommended if facilities for measurement of radioactivity are not available.Scandinavian Journal of Clinical and Laboratory Investigation 03/1981; 41(1):91-7. · 1.29 Impact Factor
- Journal of Clinical Investigation 02/1949; 28(1):144-52. · 12.81 Impact Factor
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ABSTRACT: From measurements in eighty-six adults it is shown how the distribution volume of [51Cr]EDTA, as an estimate of the extracellar fluid volume (ECV), can be determined accurately using a simplified single injection method. The method only needs drawing of a few blood samples 3-5 h after a quantitative i.v. injection of [51Cr]EDTA and measurement of the subject's body weight. The glomerular filtration rate (GFR) can be calculated from the same few data, and with it, the ratio ECV/GFR or the reverse ratio GFR/ECV. These easily determined ratios might be relevant measurements of the kidney's main function: regulation of composition and size of the extracellular fluids, since they indicate how often 'that which is to be regulated' (i.e. the extracellular fluids) comes into contact with 'the regulator' (i.e. the kidney).Scandinavian Journal of Clinical and Laboratory Investigation 11/1980; 40(6):567-73. · 1.29 Impact Factor