Rita G. Nunes1, Ivana Drobnjak2, Stuart Clare3, Peter Jezzard3, Mark Jenkinson3
1Robert Steiner MRI Unit, Imaging Sciences Department, MRC Clinical Sciences Centre, Hammersmith Hospital, Imperial College London, London, United Kingdom; 2Centre for Medical Image Computing, University College London, London, United Kingdom; 3Oxford Centre for Functional Magnetic Resonance Imaging of the Brain, University of Oxford, Oxford, United Kingdom
Echo-planar diffusion-weighted images can display significant geometric distortions due to eddy current fields. Several diffusion preparation schemes have been proposed, which can null eddy currents with a single time constant. We use an MRI simulator to compare the performance of three such sequences in the presence of multiple components, and investigate whether affine registration is capable of correcting for the resulting distortions. Our study confirms that, in general, doubly-refocused sequences perform better than single spin-echo approaches, and suggest that when the use of two refocusing pulses is not desirable, it may be preferable to use a modified single spin-echo sequence.