[Contribution of axial computer assisted tomography to the diagnosis of aresorptive hydrocephalus].

In a comparative study, 18 patients presenting with progressive mental deterioration were investigated by means of radio-isotopic cisternography and by computerized axial tomography (CAT) in order to establish morphological criteria for CAT which would enable malresorptive hydrocephalus and atrophic hydrocephalus to be differentiated. Except for one case, malresorptive hydrocephalus was characterized by supraand infratentorial ventricular dilatation without any signs of cortical atrophy of the convexity. In most cases, ventricular dilatation was more important in cases of malresorptive hydrocephalus and, in 6 out of 7 cases, the trigone and the occipital horns were particularly dilated. Only in malresorptive hydrocephalus did we find less than juxtaventricular aedema greater than possibly indicating compensating transependymal absorption of cerebrospinal fluid. In atrophic hydrocephalus, on the other hand, CAT shows a moderate degree of ventricular dilatation associated with dilatation of the cortical sulci.