CNS-Effects from Subarachnoid Injections of Iohexol and the Non-Ionic Dimers Iodixanol and Iotrolan in the Rabbit

The neural tolerance of the new non-ionic dimer iodixanol was compared with that of the clinically used monomer iohexol and the dimer iotrolan. Behaviour of non-anaesthetised rabbits was monitored for 3 hours after intracisternal injection, at a dose-volume of 1 ml/kg of iodixanol 150 mg I/ml, iodixanol 320 mg I/ml, iohexol 350 mg I/ml, or iotrolan 300 mg I/ml (10 rabbits in each group). Iotrolan induced generalised seizures in 5 rabbits, iodixanol 320 mg I/ml in 2 rabbits, and iodixanol 150 mg I/ml in one rabbit. No excitative changes were observed in rabbits injected with iohexol, but compared with the dimeric contrast media the difference was not significant. Iohexol produced significantly more severe depressive changes than iodixanol 150 mg I/ml (p<0.01), iodixanol 320 mg I/ml (p<0.05), and iotrolan 300 mg I/ml (p<0.05). The results indicate that the excitative neurotoxic potential of the dimer iodixanol is likely to be lower than that of the clinically used dimer iotrolan, but slightly higher than that of iohexol. It may be expected that both dimers will produce a lower frequency of minor neurological adverse reactions than iohexol.

The history of Swedish neuroradiology

The history of Swedish neuroradiology is reviewed.

Neurotoxicity of water-soluble contrast media

A review is given of the development of the water-soluble contrast media (CM) with particular attention to the frquency of neurological complications. A remarkable improvement was achieved following the introduction of the nonionic agent metrizamide in 1974, and a further decrease in neurotoxicity was obtained with the newer nonionic monomers, which have multlple hydroxyl groups included at different sites of the molecule. Theoretical considerations and experimental studies suggest that the neurotoxicity of the new nonionic dimeric agents shuold be at least within the low range seen with the monomeric ones, but further experience is needed before definite conclusions can be drawn in this respect. The mechanisms responsible for the neurological complications seen with CM are unknown but certain critical groups on the CM molecules are known. Several animal models have been developd, which may help predict the degree of neurotoxicity.