The influence of concentration and dose upon the extravascular distribution of intra-arterially injected meglumine diatrizoate.

The dose and concentration of an intra-arterially injected contrast medium, when increased approximately fivefold from a slightly hypotonic solution, produced lower tissue distribution volumes and lower extravascular diatrizoate fractions in the rat. A further fivefold increase in dose (to 1 ml/kg) with little change in concentration produced even lower early distribution volumes. Increases of concentration and dose caused a higher percentage of the contrast medium to remain within the vasculature, presumably as a result of extraction of tissue water by the hypertonic medium. Changes in the concentration of the contrast medium affected its distribution volume for a longer time than corresponding changes in the actual dose. The use of the more concentrated contrast media at higher doses should be expected to give better radiologic detail on angiograms.