Object: The purpose of this study was to establish a standard curve to demonstrate normal age-related changes in the proportion of intracranial cerebrospinal fluid (CSF) space in intracranial volume (ICV) during each decade of life.
Methods: Using volumetric computerized tomography (CT) scanning and computer-guided volume measurement software, ICV and cerebral parenchymal volume (CPV) for each decade of life were measured and the intracranial CSF ratio was calculated by the following formula: percentage of CSF = (ICV - CPV)/ICV x 100%. The standard curve for age-related changes in normal percentages of intracranial CSF was obtained.
Conclusions: Based on this standard curve, the percentage of intracranial CSF rapidly increased after the sixth decade, seeming to reflect the brain atrophy that accompanies increased age.