Changes on computed cranial tomography with aging: intracranial fluid volume.

A semiautomated computer analysis was developed to estimate fluid volumes in each hemicranium from computed tomography scans. The method was used to estimate total ventricular and sulcal fluid in 123 normal subjects aged 23-88 years. A wide range of normal values was found. The trend was for the estimated ventricular and sulcal fluid volumes to remain relatively constant until age 60 and then to increase at an increasing rate thereafter. Ventricular enlargement occurred in the absence of sulcal enlargement and vice versa. The estimate of the volume of the ventricles was related to skull size. When this was taken into account, the size of the ventricles showed no sex difference. The cranial cavity was larger in men than in women, and, in both genders, the left hemicranium and the left ventricle were larger on the average than their right counterparts. The limitations of computed cranial tomography as a quantitative tool are discussed in detail.