Modification of periventricular hypodensity in hydrocephalus with ventricular reflux in metrizamide CT cisternography

An analysis of metrizamide computed tomography (CT) cisternographic findings in cases of communicating hydrocephalus has been carried out. Serial observations of the density in the periventricular area in 19 cases with metrizamide ventricular reflux have revealed the following different patterns: (a) precontrast periventricular hypodensity diminishing after CT cisternography and possibly indicating transependymal metrizamide migration (two cases); (b) periventricular hypodensity unchanged (two cases); (c) minimal periventricular hypodensity with slight rise in its attenuation values after ventricular metrizamide reflux (four cases); and (d) no periventricular hypodensity and no change after reflux (six cases). Our preliminary experience indicates that the presence of periventricular hypodensity with an increase in its attenuation values following ventricular reflux of metrizamide is possibly a criterion that may be used in favor of a cerebrospinal fluid shunting operation.