Intravascular contrast media and the blood-brain barrier. Testing the new nonionic agent ioxilan

The effects of diatrizoate, iohexol, and ioxilan on the blood-brain barrier (BBB) were investigated in normal and hypertensive rats. Anesthetized Wistar rats received 14C-inulin as an indicator for BBB disruption. Diatrizoate, iohexol, or ioxilan (350 and 175 mgI/mL) or normal saline was then injected into the carotid artery (2 mL in 30 seconds). Twenty minutes later, the cardiovascular system was flushed, the brain removed, and each hemisphere was digested. BBB disruption, expressed as counts/minute/mg protein, was compared for each hemisphere in each group by analysis of variance. BBB damage in the diatrizoate-350 group was significantly greater than that in all other groups. No significant BBB damage resulted from iohexol or ioxilan relative to normal saline.