To assess the impact of computed tomography (CT) on patient care, a cohort of patients with suspected hydrocephalus admitted before installation of CT was compared to a similar cohort admitted after installation of CT. The after CT cohort used significantly fewer pneumoencephalograms and radionuclide brain scans. The average cost of neurodiagnostic evaluation was 22% less after CT. However, speed of workup, therapy, institution of therapy, discharge plans, and discharge diagnoses were not different for the two cohorts. We conclude that CT has made the diagnostic evaluation of patients who otherwise would have required pneumoencephalography for suspected hydrocephalus less expensive and less hazardous.