Aging, dementia, and brain atrophy: a longitudinal computed tomographic study.

Studies involving linear measurements of ventricular size and a volumetric measurement of the cerebrospinal fluid (CSF) space were performed on elderly subjects with mild dementia of the Alzheimer type and on age-matched controls. Forty-five subjects were studied twice at a 1 year interval; linear ventricular measurements showed not only a greater degree but a more rapid evolution of brain atrophy in individuals with mild dementia as compared with controls. An additional 12 normal subjects were studied twice over a 1 year period with volumetric estimates of the CSF space, which demonstrated development of significant brain atrophy within 1 year, while linear measurements on the same scans showed no significant change. The volumetric method is regarded as a more sensitive indicator of brain volume and is potentially useful in further studies in dementia.