Computerized axial transverse tomography in normal pressure hydrocephalus.

Twenty patients with normal pressure hydrocephalus were examined by computerized axial transverse tomographic (CT) scanning and the results were compared with pneumoencephalographic findings and clinical responses to ventricular shunting. The CT scan revealed significant cortical atrophy, not demonstrated by pneumoencephalogram in seven patients. The cortical atrophy was confirmed by autopsy in one case. This examination also revealed greatly enlarged ventricles (25 to 40 per cent of intracranial volume) in eight patients up to 4 years after ventricular shunting. There was no relationship between the presence or absence of cortical atrophy, or the postoperative ventricular size, and the clinical responses to ventricular shunting. Current concepts of normal pressure hydrocephalus must be revised in view of these findings.