Abstract #0797

High B-Value HARDI Analysis in Neonates Scanned at Term-Equivalent Age Reveals Correlation Between Apparent White Matter Fibre Density and Immaturity at Birth

Jacques-Donald Tournier¹,², Serena J. Counsell³, David A. Raffelt¹, Nora Tusor⁴, Phumza Nongena⁴, A. David Edwards³, Joseph V. Hajnal³, Alan Connelly¹,²

¹Advanced MRI development, The Florey Institute of Neuroscience and Mental Health, Melbourne, Victoria, Australia; ²Department of Medicine, University of Melbourne, Melbourne, Victoria, Australia; ³Centre for the Developing Brain, King's College London, London, United Kingdom; ⁴Department of Medicine (Paediatrics), Imperial College London, London, United Kingdom

Preterm birth is associated with poor neurodevelopmental performance, and diffuse white matter injury is frequently observed. In this study, we investigate the effect of gestational age at birth on a new direction-specific measure, the apparent fibre density (AFD), using a high b-value, high angular resolution diffusion imaging (HARDI) acquisition. 31 neonates were scanned at term, and the AFD correlated with gestational age, regressing out post-menstrual age at scan. Significant correlations were observed bilaterally in most major white matter tracts, consistent with previous DTI findings. AFD allows the identification of direction-specific changes, making interpretation of results more straightforward than using scalar measures.