Nephrographic density and renal diatrizoate content in experimental acute renal failure

Reversible acute renal failure (ARF) was induced in rats by intramuscular injection of glycerol. In these animals and controls, renal concentrations of 125I-labelled sodium diatrizoate, injected intravenously in doses similar to those used clinically, were compared with the density of the nephrogram, subjectively assessed under carefully controlled conditions. Though a good statistical correlation existed between renal diatrizoate concentration and nephrographic density, individual variation was wide. At any given level of renal iodine concentration, nephrograms were judged to be denser in ARF than in controls. This was not due to differences in whole-body opacification or renal size, but was partly explained by the greater visibility of renal outlines on plain films in ARF. However, though at all doses of diatrizoate renal iodine concentrations were higher in controls, differences in nephrographic density were in general difficult to detect.