Glomerular filtration rate estimated by X-ray fluorescence technique in children: comparison between the plasma disappearance of 99 Tc m -DTPA and iohexol after urography

The total plasma disappearance of the non-ionic contrast medium iohexol was determined by X-ray fluorescence technique following intravenous urography in 10 children aged between 2 and 13 years. For comparison the plasma disappearance of 99Tcm-DTPA was estimated both 2 days before and simultaneously with the iohexol study. High correlations between the three sets of data were found and no change in the glomerular filtration rate was detected following injection of contrast medium. It was also found that reliable estimates of the glomerular filtration rate can be obtained from two plasma samples of 1 ml each, taken 3 h and 4 h after the injection of the contrast medium.