Simultaneous Urography and Determination of Glomerular Filtration Rate

Abstract

The total plasma clearance of iohexol at urography and ⁵¹Cr-EDTA was compared in 31 patients with di- or tetraparesis. A reference ⁵¹Cr-EDTA clearance was also performed 24 hours prior to the urography. The GFR was calculated from one, 2 or 4 plasma samples collected 180, 210, 240 and 270 min after the injection. An X-ray fluorescence analyzer was used for the analysis of iohexol in plasma as well as the contrast medium clearance calculations. It was shown that single or multiple sample clearance of iohexol and ⁵¹Cr-EDTA were equivalent methods for measurement of the GFR. The GFR was not affected by iohexol in a dose routinely used for urography. It was concluded that the patient comfort is improved if ⁵¹Cr-EDTA clearance is replaced by contrast medium clearance in association with urography.