Radionuclide cisternography

Computed tomography of the brain in the diagnosis of and prognosis in normal pressure hydrocephalus

Thirty-eight patients with normal pressure hydrocephalus were examined by CT before and after a ventriculo-peritoneal shunt operation. Evans ratio, periventricular hypodensity and width of hemispheric sulci, sylvian fissures, cella media, temporal horns and third and fourth ventricle were examined. Twenty-eight patients improved after the operation while 10 were unchanged (non responders). Those patients who improved had more often enlarged third ventricle, enlarged temporal horns and normal sylvian fissures than those who did not improve. No single CT parameter or combination of CT parameters alone could identify responders and non-responders. The ventriculo-peritoneal shunt operation reduced ventricular size (Evans ratio, cella media width), abolished periventricular hypodensity and reduced width of the temporal horns and third ventricle in both responders and non-responders. Reduction of the width of the third ventricle correlated to clinical improvement.

The effect of metrizamide on the electroencephalogram: a prospective study in 61 patients

A prospective study was made of changes in the electroencephalogram after the use of metrizamide for myelography and posterior fossa cisternography in 61 patients (62 studies). The EEG changed in 21 patients (34%); 3 of these had had previously abnormal records, and the abnormalities were accentuated on the second recording. Eight developed paroxysmal activity, including spike and wave in 1. EEG changes appeared 24 to 48 hours after the use of metrizamide in 6 patients whose intervening EEGs were normal. The percentage of records that changed tended to increase as metrizamide was brought to more rostral levels. Symptoms following the use of metrizamide were reviewed in 58 patients. Although there were no seizures in the present series, seizures did occur with subsequent use of metrizamide in 3 other patients at our institution. Previous reports may have underestimated the frequency of EEG changes after metrizamide since these may require 24 to 48 hours to develop. The appearance of such activity suggests that the use of metrizamide in patients with known seizure disorders, the anatomical level to which metrizamide is brought during radiography, removal of contrast medium, and further investigation of premedication with anticonvulsants all require careful consideration when use of metrizamide is being contemplated.

Aseptic meningitis and hydrocephalus after posterior fossa surgery

In an attempt to define the tissue of origin of substances causing aseptic meningitis and secondary hydrocephalus after posterior fossa surgery, analysis of several marker substances from blood, brain, tumour and muscle in the CSF was performed early in seven postoperative patients. No clear pattern emerged which could relate the substances, CSF reaction, and meningeal scarring. The effects of various factors such as contrast studies, drainage, and steroids were also not clear. Review of the literature reveals that all four tissues can cause inflammation. Certain facts about the anatomy of the basilar cisterns and arachnoid villi probably make them logical sites for problems in CFS circulation. Children, for several reasons, are most susceptible to this complication. The complexity of factors in human cases suggests that the problem should be studied in an animal model.

Side effects after lumbar myelography with dimeglumine iocarmate (Dimer-X). Further experiences

Lumbar myelography with dimeglumine iocarmate was performed in 90 cases premedicated with diazepam (Valium). EEG was performed before, as well as 3 and 24 hours after myelography. The use of diazepam interfered to some extent with the interpretation of the EEG. In 3 cases EEG abnormalities occurred 3 hours after myelography, most probably ascribable to Dimer-X. No further changes were found in the 24-hour recording. Immediate side effects were few and mild and seizures did not appear. The EEG abnormalities were equally distributed among patients with and without side effects.