Courtesy of Shaun Stone, this image demonstrates the MR-based neuroimaging technique of diffusion tensor imaging (DTI), which allows estimation of microstructural integrity, location, orientation and anisotropy of the brain’s white matter tracts. Fractional anisotropy (FA) is a measure of anisotropic diffusion of water molecules within the white matter fibres of the brain, and FA maps for the visualisation above were generated using diffusion-weighted images taken by a 3T MRI scanner at the University of Aberdeen.
Eigenvectors (ε1, ε2, ε3) give the directions of water diffusion, and the corresponding eigenvalues (λ1, λ2, λ3) give the magnitude of the diffusion process in each direction. The top row of images shows the principal eigenvector modulated to the FA map as an RGB colour map, while the bottom row of images show the principal eigenvector displayed as Lines RGB. The three colours correspond to the principal diffusion direction, with proportional intensity according to the FA value. Red lines = left/right. Blue lines = superior/inferior. Green lines = anterior/posterior.
Images shown were obtained from a 61-year-old healthy male who was originally part of the Aberdeen Children of the Nineteen Fifties (ACONF) cohort, who returned for late-life brain imaging as part of the Stratifying Resilience and Depression Longitudinally (STRADL) project.
Shaun’s research, under the guidance of Prof Alison Murray and Dr Gordon Waiter, aims to develop prediction models of cognitive reserve using a machine learning approach. This project is part funded by SINAPSE and industry partners, IXICO PLC.