EFFECTS OF ISOSMOLAR CONTRAST-MEDIA ON THE RENAL CORTICAL BLOOD-FLOW IN MICE

Purpose: In vivo fluorescence microscopy was used in experimental stud ies of renal cortical microcirculation in mice. The effects of i.v. in fusion of a nonionic monomeric contrast medium (iohexol), a nonionic d imeric contrast medium (iodixanol), and mannitol of corresponding osmo lalities were studied. Results: All infusions produced marked effects on the distribution and velocity of renal cortical blood flow. Renal c ortical blood flow was inhomogeneous as regards the different capillar ies. There was an initial rapid rise in the blood flow in some capilla ries after all infusions, while decreased flow was seen in other capil laries. The initial increase in renal cortical blood flow (RCBF) was s ignificantly (p<0.05) more pronounced after infusion of iohexol than a fter infusion of mannitol 0.69 mol/l. In all other respects, the effec ts of contrast media on RCBF were the same as the effects of mannitol solutions with a corresponding osmolality. The effects of each contras t medium were the same as those of mannitol of corresponding osmolalit y. In the capillaries showing increased blood flow, the peak value was encountered slightly later after the infusion of iodixanol than after the infusion of iohexol. This was considered to be related to differe nces in viscosity rather than osmolality. Conclusion: The difference i n osmolality between iodixanol and iohexol is of no significance with regard to their effects on RCBF.