Simulation of Optimal Echo Times to Maximize BOLD Sensitivity in the Orbitofrontal Cortex for FMRI

Sebastian Domsch¹, Lothar R. Schad¹

The orbitofrontal cortex (OFC), important for decision-making and reward processing, is affected by susceptibility gradients (SG) causing signal drop outs and image distortions in fMRI using EPI. In subcortical brain areas, BOLD sensitivity (BS) depends critically on echo time (TE). In this work, optimal TE for single EPI slices are calculated via BS simulations considering local T2star and SG values to maximize BS in the OFC. It shows that optimal TEs increase in foot-head direction from about 20ms to 40ms for AC-PC section orientation. Further, the results show good consistency over all subjects.