MAGNETIC-RESONANCE-IMAGING EVALUATION OF THE EFFECTS OF AGING ON GRAY-WHITE RATIO IN THE HUMAN BRAIN

A previous neuropathological report noted a non-linear pattern of chan ge in cerebral grey-white matter ratio during ageing. In that report, grey-white ratio decreased from age 20 to age 50, then increased in el derly subjects. The objective of the current study was to attempt to r eplicate this pattern of age-related change in the grey-white ratio in living human subjects using quantitative magnetic resonance imaging s egmentation analysis. We measured the grey-white ratio in 78 subjects between the ages of 19 and 77 years, using a computer segmentation alg orithm with magnetic resonance images. In agreement with the previous neuropathological report, the current in vivo magnetic resonance study found that the grey-white ratio declined from age 20 to age 50, then increased in elderly subjects.