Siawoosh Mohammadi1, Zoltan Nagy1, Harald E. Moeller2, David Carmichael3,4, Mark Symms3, Oliver Josephs1, Nikolaus Weiskopf1
1Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, University College London, London, United Kingdom; 2Max Planck Institute for Human Cognitive & Brain Sciences, Leipzig, Germany; 3Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, United Kingdom; 4MRI unit, National Society for Epilepsy, Chalfont St. Peter , United Kingdom
Imaging artefacts, which perturb diffusion-weighted images, can bias the estimated diffusion tensor. Important sources of imaging artefacts in DTI are eddy current fields, gradient nonlinearities or mis-calibration of the gradient amplitude. They can be modelled by introducing the concept of a local perturbation field (LPF). In this study, we used first-order perturbation theory to introduce a physically-informed model that estimates and corrects for the effect of LPFs. Using phantom and human DTI measurements on two different scanners we were able to estimate the LPFs and improve the quality of FA maps without requiring vendor-specific information.