Endothelial permeability increase produced by angiographic contrast media.

Permeability changes of the thoracic aortic wall of the rat were examined under light microscopy using the silver staining method. Methylglucamine salts of common angiographic contrast media and metrizamide were tested using a constant iodine concentration. Statistically significant differences between these media were found. The contrast agents were divided into three groups according to the extent of increasing endothelial damage: 1. Metrizamide and methylglucamine diatrizoate, 2. Methylglucamine metrizoate in the presence of calcium and methylglucamine iodamide, 3. Methylglucamine iothalamate. The osmolality of the contrast media was determined. The ionic contrast agents were equal in hypertonicity and metrizamide was nearly isotonic. The endothelial damage caused by the radiographic contrast media seems to depend both on chemical structure and on hypertonicity.