Steffen Volz1, Martina F. Callaghan1, Oliver Josephs1, and Nikolaus Weiskopf1,2
1Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, UCL, London, United Kingdom, 2Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
fMRI studies can suffer substantially from BOLD
sensitivity loss due to susceptibility-related magnetic field inhomogeneities. We
developed an automated algorithm for optimising arbitrary EPI protocols with
respect to BOLD sensitivity based on numerical simulations and a multi-subject
field map database, saving time and expensive measurements. In contrast to
previous experimental optimization approaches that were limited e.g. to z-shim,
gradient polarity and slice tilt for a specific EPI protocol, this algorithm
optimizes on a larger parameter space including resolution, echo time and slice
orientation. Results were compared to earlier experimental approaches and
verified by BOLD sensitivity measurements in healthy volunteers.
