Measurement of Glomerular Filtration Rate in Man Using DTP A-⁹⁹^mTc

Abstract

The aim of this study was the evaluation of the mechanism of renal excretion of DTPA-^99mTc in man. For this purpose the renal clearances of DTPA-^99mTc and diatrizoate-¹³¹I were simultaneously determined in 21 patients by means of vesical catheterization and of continuous venous infusion of the tracers. The mean ratio between the clearances of DTPA-^99mTc and diatrizoate-¹³¹I was 0.92 ± (SD) 0.06 (p < 0.001). In order to demonstrate a possible tubular reabsorption of the studied tracer, its clearance was determined simultaneously with those of diatrizoate-¹³¹I and urea in 10 patients at different urine flow rates, i. e., under basal conditions and at high urine flow induced by hydration. In contrast to the urea clearance, changes in urine flow rate did not significantly affect the clearances of either tracer. In 12 patients the clearance of DTPA-^99mTc was also determined by means of external counting over the bladder. The mean ratio between the clearances obtained by external counting and by vesical catheterization was 1.03 ± (SD) 0.05. These results demonstrate that the renal clearance of DTPA-^99mTc is slightly lower than the glomerular filtration rate as measured by diatrizoate-¹³¹I. Since its clearance may be easily measured by means of the noninvasive method of external counting over the bladder, DTPA-^99mTc represents a valuable tool in the determination of glomerular filtration rate in man.

Functional MR of the kidney

“…Three to four consecutive urine ( U ) collections are obtained at timed intervals of about 20 min with serum collections bracketed at the start and end of each collection. 99"TcDTPA clearance was derived by counting the radioactivity in a scintillation counter using standard methods ( 7,8). By measuring the TI using a 90"-t-90" pulse sequence at 10 Mhz (Praxis, San Antonio, TX) in the serums and urines and correlating the results of 1 /T1 to known standard serial dilutions measurements of the baseline serum and urine, the GdDTPA GFR could be determined by…”

“…GdDTPA is analogous to 99mtechnetium( Tc)-DTPA, a true filtration marker which is wideIy used to measure urinary clearance ( 7,8). Therefore, it should be possible to substitute counts per minute which is proportional to the concentration of 99"TcDPTA in the serum and urine with the T1 relaxation rate ( 1 / T l ) , which is dependent upon the GdDTPA concentration in these fluids ( 9 ) .…”

Predicting Glomerular Function from Adjusted Serum Creatinine

“…Several reports indicate C-DTPA gives an accurate measurement of GFR [23,24]. Renal function was at steady state.…”

Prediction of glomerular filtration rate from serum concentration of cystatin C: comparison of two analytical methods

“…GFR was measured as the renal clearance of 99m Tc-DTPA [1,29]. The results were adjusted to the body surface of 1.73m 2 .…”