Rita Gouveia Nunes1, 2, Shaihan J. Malik2, Joseph V. Hajnal2
1Institute of Biophysics & Biomedical Engineering, Faculty of Sciences, University of Lisbon, Lisbon, Portugal; 2Robert Steiner MRI Unit, Imaging Sciences Department, MRC Clinical Sciences Centre, Hammersmith Hospital, Imperial College London, London, United Kingdom
Echo-planar imaging is widely used for diffusion-weighted imaging despite its high sensitivity to field in-homogeneities. Although single-shot fast spin-echo images do not have this limitation, the signal is highly sensitive to the phase of the magnetization prior to the start of the refocusing train (CPMG condition). Brain pulsation and bulk patient motion during diffusion sensitization lead to unpredictable phase patterns, while scanner vibrations produce reproducible non-linear phase modulations. A prospective method for correcting for spatially non-linear phase structures using tailored RF pulses is presented and shown to be effective in phantoms.