Abstract #0275

Converging Microstructural Evidence in Prodromal and Early Alzheimers Disease: Alteration of Commissural and Association Pathways, Sparing of Motor Pathways

Gwenaelle Douaud¹, Saad Jbabdi¹, Timothy Edward Behrens¹, Ricarda Menke¹, Achim Gass², Andreas Monsch³, Anil Rao⁴, Brandon Whitcher⁴, Gordon Kindlmann⁵, Paul M. Matthews⁴, Stephen Smith¹

¹FMRIB Centre, University of Oxford, Oxford, Oxfordshire, United Kingdom; ²Departments of Neurology and Neuroradiology, University Hospital, Basel, Switzerland; ³Memory Clinic, Basel, Switzerland; ⁴GSK, CIC Hammersmith Hospital, London, United Kingdom; ⁵Department of Computer Science and Computation Institute, University of Chicago, Chicago, IL, United States

Using TBSS, we investigated white matter abnormalities in the largest diffusion study including healthy elderly, mild cognitive impairment and Alzheimers disease. We also used the mode of anisotropy which specifies the shape of anisotropy. All diffusion tensor indices converged to show that the uncinate fasciculus, cingulum bundle, corpus callosum, anterior commissure and superior longitudinal fasciculus were affected. We found a regional increase of mode and fractional anisotropy, often considered atypical for a degenerative disorder. Using tractography, we directly and quantitatively showed that these local increases were related to the neuropathological sparing of the motor-related pathways compared with the superior longitudinal fasciculus.