Reactions to suboccipital injection of water-soluble contrast media in rabbits

EEG changes 24 hours after myelography with metrizamide

A prospective study of EEG changes following metrizamide myelography was made on 34 patients aged 17-79 years. EEGs were recorded just before and 22-26 hours after myelography. Usually 8-10 ml of metrizamide was injected by either lumbar or lateral cervical puncture. The concentration of metrizamide was relatively high. EEGs were abnormal in 15 out of the 20 patients whose baseline EEGs were normal. EEGs deteriorated in 10 of the 14 patients whose control tracings were abnormal. High voltage delta activity and/or a great deal of theta activity were common abnormalities. Three patients showed triphasic waves. No relationships were found between the EEG changes and clinical variables. But central nervous system involvements by metrizamide tended to be accompanied by a severe EEG slowing.

Cardiovascular reactions to myelography with watersoluble contrast media

Arterial blood pressure and heart rate were recorded for 5 to 7 h during myelography with iothalamate meglumine and metrizamide in 23 rabbits. After 0.6 ml iothalamate meglumine containing 280 mg I/ml a significant decrease in blood pressure and signs of circulatory failure were found. After identical doses of metrizamide and after reduction of the dose of iothalamate meglumine to 0.4 ml containing 140 mg I/ml no significant fall in blood pressure was recorded. A decrease of blood pressure was always accompanied by a decrease of heart rate. Arterial blood pressure and heart rate during experimental myelography are suggested as useful variables in the evaluation and comparison of new contrast media for myelography.

Cerebrospinal fluid imaging using serial metrizamide CT cisternography

Twenty-five patients studied by serial metrizamide (Amipaque) CT cisternography were used to analyze CSF kinetics. Delayed CSF flow patterns were noted in 7 patients, while intermediate patterns occurred in 4. The abnormal cisternogram was characterized primarily by ventricular reflux and stasis and secondarily by diminution of the parasagittal blush and a periventricular rim of decreased absorption. The intermediate group had minimal ventricular stasis after 24 hours and a normal parasagittal blush. After clinical and biochemical evaluation of the patient with dementia, CT scanning is usually indicated. If a profile suggestive of communicating hydrocephalus emerges, CSF kinetics can be monitored dynamically by CT scanning with metrizamide enhancement.

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.