“…In EEG-fMRI of epileptic patients, it is preferable to scan the whole brain, since the generator of scalp spikes may, within reason, be anywhere. Other strategies include optimisation of the slice orientation [Deichmann et al, 2003;Ojemann et al, 1997], the use of diamagnetic materials to correct for field perturbations [Wilson et al, 2002], and zshimming methods, which apply refocusing pulses to correct for local field inhomogeneities in the slice selection direction [e.g., Cordes et al, 2000, Gu et al, 2002. All of these techniques have drawbacks, such as precluding whole brain coverage, reducing the temporal resolution, reducing the BOLD contrast to noise ratio, or, in the case of passive diamagnetic shims, discomfort for the patient during the course of a 90-min scanning session.…”