[Contrast medium clearance as a measure of kidney function in patients with renal artery stenoses]

The quantitative estimation of the characteristic radiation from 127I following external stimulation by 241americium photons makes it possible to estimate iodine concentration. The plasma concentration of non-ionic contrast media handled by glomerular filtration was measured in 16 patients with renal artery stenosis. This was done during diagnostic angiography or percutaneous dilatation, either at an early stage (one to two hours) or at a late stage (five to eight hours). Assuming an exponential excretory function, a clearance value could be calculated. The results were compared with the clearance values of a tubular excreted radiopharmaceutical (99m technetium-MAG3). Despite the different excretory mechanisms, there was a statistically significant correlation between the scintigraphic and contrast clearances at the later time (r = 0.85, p is less than 0.001). At the earlier stage, there was no signification correlation (r = 0.46, p is greater than 0.05). The correlation between the later values and the serum creatinin level was moderately significant (r = 0.55, p less than 0.05).