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.