  Single-shot gradient recalled echo planar imaging (EPI) is the primary tool
for functional magnetic resonance imaging (fMRI). The image often suffers from
signal drop near the air-tissue interface, such as the amygdala and regions of
the orbitofrontal lobe. An effective way to correct for this type of artifact
is by applying multi-shot EPI using different z-shimming. Unfortunately, the
scanning efficiency is significantly lowered. More recently, a new technique
called volume-selective z-shim was proposed to implement z-shim compensation to
only specific slices with large susceptibility effects. The high imaging
efficiency of volume selective z-shim makes it possible to substitute
conventional EPI for whole brain studies. In this study two fMRI experiments
were conducted to compare volume- selective z-shim and conventional EPI while
subjects performed tasks on face stimuli. The comparison was focused on three
brain regions: amygdala, hippocampus, and fusiform gyrus. Our results indicate
that despite fewer volumes collected during the same amount of scan time,
volume-selective z-shim showed statistically higher activation in brain regions
susceptible to signal loss while minimal differences were observed elsewhere.
