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.