Computed tomography and pneumoencephalography compared to conductance to outflow of CSF in normal pressure hydrocephalus

The conductance to outflow of CSF Csub(out) was measured in 66 patients with normal pressure hydrocephalus (NPH). All patients were investigated with computed tomography (CT); 34 of the patients also had pneumoencephalography (PEG). Periventricular hypodensity on CT indicates a low Csub(out). Cortical sulci smaller than 1.9 mm on CT indicate a low Csub(out), while wide cortical sulci do not exclude a low Csub(out). There was a good correlation between ventricular size on CT and PEG, but the ventricular size is unrelated to Csub(out). No findings on PEG indicate a low Csub(out). (orig.)