Results of the use of a new water-soluble contrast medium (metrizamide) in the posterior fossa of the baboon.

An investigation was made of the use of a new water-soluble contrast material (metrizamide) for posterior-fossa radiography in the baboon. The experiments showed that the concentration of metrizamide needed to produce adequate radiographs from sub-occipital injections into the posterior fossa always produced generalized seizures. Intraventricular injection produced excellent radiographs from metrizamide concentrations, which did not result in either clinical or EEG seizure activity. Seizures, when they occurred, were easily controlled with pentobarbitone and phenytoin. In all the experiments, ECG changes were found, which disappeared after some hours.