Abstract
Computerized tomograms were studied of 67 adults whose lumbar pneumoencephalograms were normal or showed ventricular dilatation with or without widening of the sulci. The maximum ventricular area, measured from 80 x 80 matrix printouts, correlates well with measures of ventricular size on the pneumoencephalogram. An area of 10 cm2 is suggested as the upper limit of normal. The correlation between measures of sulcal width on computerized tomography and pneumoencephalography is less precise, but normal sulci and gross degrees of cortical atrophy can be identified.