Diffusion Tensor Imaging of Brain White Matter Changes Across the Lifespan

Catherine Lebel¹, Myrlene Gee¹, Richard Camicioli², Marguerite Wieler², Wayne Martin², Christian Beaulieu¹

Lifespan studies of the normal human brain link the development processes of childhood with the degenerative processes of old age. Many diffusion tensor imaging (DTI) studies evaluate changes over narrow age ranges; few examine the lifespan. We used DTI to measure age-related changes in 12 white matter tracts in 392 healthy volunteers aged 5-83 years. Fractional anisotropy increased until adulthood, then decreased, while mean diffusivity followed an opposite trend. Trend reversals occurred between 18-43 years. Frontal-temporal connections demonstrated prolonged development and late reversals, while the fornix and corpus callosum develop earliest and have the most prolonged periods of decline.