New contrast media in cerebral angiography: animal experiments and preliminary clinical studies.

The cerebrovascular toxicity of three water-soluble contrast agents with a low hypertonicity (metrizamide, ioxaglate, iopamidol) was tested. Blood-brain barrier damage after carotid injection was assessed using 32P autoradiography and fluorescent microscopy after Evans blue staining. The damage to carotid endothelium was determined using a silver staining method. Brain tissue was studied by light and electron microscopy. The studied contrast media did not damage either the blood-brain barrier or the carotid endothelium at clinical doses. Nonionic metrizamide and iopamidol have a very low brain tissue toxicity. Preliminary clinical experience indicates that the incidence of adverse reactions (pain, feeling of heat) is low. No severe adverse reactions were observed. No improvement of the radiologic information compared with the current contrast agents was observed.