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Abstract #1564

Polynomial Models of the Spatial Variation of Axon Radius in White Matter

Gemma Louise Morgan1, Rexford D. Newbould2, Brandon Whitcher2, Daniel C. Alexander1

1Centre for Medical Image Computing, University College London, London, United Kingdom; 2Clinical Imaging Centre, GlaxoSmithKline, London, United Kingdom

Axon radius r is a potentially useful clinical biomarker that can be derived from diffusion weighted imaging. However its estimation in a clinical setting is hampered by poor signal-to-noise ratio and limited sensitivity to small axon radii at low gradient strengths. In this study we introduce a technique for estimating a mean radius index ρ that exploits the spatial coherence of axon radii across the corpus callosum. Specifically, we fit a polynomial model of the spatial variation of ρ. This significantly reduces the total number of parameters to estimate and provides sensitivity to axon radius, even at typical clinical gradient strengths.