Abstract #0787

Apparent Fibre Density Shows Tract-Specific White Matter Changes in Temporal Lobe Epilepsy

David Vaughan¹,², David A. Raffelt¹,³, Jacques-Donald Tournier¹,³, Graeme Jackson¹,², Alan Connelly¹,³

¹Brain Research Institute, Florey Institute of Neuroscience and Mental Health, Melbourne, Victoria, Australia; ²Department of Neurology, Austin Health, Melbourne, Victoria, Australia; ³Department of Medicine, University of Melbourne, Melbourne, Victoria, Australia

We investigated white matter changes in Temporal Lobe Epilepsy (TLE) both in patients with hippocampal sclerosis and in patients with a normal structural MRI, using diffusion-weighted imaging data to compute the Apparent Fibre Density (AFD). This measure allows group differences to be identified in specific orientations and locations, so that pathological white matter changes may be attributed to fibres having a particular direction, even in regions containing multiple crossing tracts. Significantly decreased AFD is demonstrated in patients with TLE compared to controls, with different patterns of affected tracts seen in the hippocampal sclerosis and lesion-negative groups.