Technetium-99m-MAG3 clearance as a parameter of effective renal plasma flow in patients with proteinuria and lowered serum albumin levels.
(65/140)
Although the renal clearance of 99mTc-MAG3 is about 60% of the 131I-hippurate clearance, 99mTc-MAG3 clearance may be useful to estimate ERPF. In one study, however, proteinuria seemed to influence the MAG3/hippurate clearance ratio. In order to establish whether proteinuria or serum albumin level has influence on this ratio, a comparison was made between 99mTc-MAG3 clearance and 131I-hippurate clearance in 14 patients. There was a good linear correlation between MAG3 and hippurate clearance, although the standard error of estimate of ERPF from MAG3 was relatively large, which remained unexplained. No correlation was found between proteinuria and MAG3/hippurate clearance ratio nor between serum albumin level, GFR, FF, ERPF and the MAG3/hippurate clearance ratio. We therefore conclude that there is no correlation between proteinuria and albumin level and the MAG3/hippurate ratio. A reasonable estimation of ERPF with MAG3 can be made in patients with proteinuria and lowered serum albumin levels although the estimation may be less accurate. (+info)
Technetium-99m-MAG3 versus iodine-123-OIH: renal clearance and distribution volume as measured by a constant infusion technique.
(66/140)
The renal clearance and distribution volume of 99Tc-mercaptoacetyltriglycine (MAG3) and 123I-o-iodohippurate (OIH) were determined separately in six normal male volunteers using the constant infusion clearance technique in order to validate single injection clearance techniques and subsequently the normal values for these parameters. MAG3 renal clearance was 257 +/- 24 ml/min/1.73 m2, compared to the OIH clearance of 556 +/- 46 ml/min/1.73 m2 resulting in a MAG3/OIH clearance ratio of 0.47 +/- 0.06. The MAG3 and OIH apparent distribution volumes at steady-state were 14.8 +/- 3.7 and 19.4 +/- 5.3 liters, respectively, the latter value approximating the extra cellular fluid volume. Urinary excretion in the 0-30-min period after intravenous administration was 64.4 and 70.2% for MAG3 and OIH, respectively. This investigation revealed some significant differences in the normal values of the renal clearance and distribution volume of MAG3 compared with other studies. (+info)
Diuretic renography in hydronephrosis: delayed tissue tracer transit accompanies both functional decline and tissue reorganization.
(67/140)
Totally automatic definition of renal regions of interest from 99mTc-MAG3 renograms: validation in patients with normal kidneys and in patients with suspected renal obstruction.
(69/140)
Pharmacokinetics of technetium-99m-MAG3 in humans.
(72/140)
Technetium-99m-mercaptoacetylglycylglycylglycine (99mTc-MAG3) is introduced to replace o-iodohippurate (OIH) for renal function studies. For interpretation of clinical findings, extensive pharmacokinetic studies were performed on patients. These showed that 99mTc-MAG3, compared with OIH, has a higher plasma-protein binding, an essentially higher intravascular concentration, a smaller volume of distribution and, with practically identical biologic half-lives, a correspondingly lower clearance. Simultaneous steady-state measurements resulted in a 1.5-fold higher clearance of OIH than of 99mTc-MAG3 (n = 124). Competitive inhibition of the tubular transport system by p-aminohippurate (PAH) (20 patients) revealed a distinctly higher suppression of the 99mTc-MAG3 clearance than of OIH which indicates a lower affinity of the 99mTc complex to the tubular cell. The plasma extraction efficiencies of both agents, measured during surgery (n = 5), did not indicate an extrarenal elimination of 99mTc-MAG3. This new radiopharmaceutical is a pragmatic alternative to OIH and offers advantages not only for scintigraphic imaging but is also suited for quantitative renal function studies. (+info)