Dear experts,

I have encountered a problem regarding field map correction in FSL. FSL help states that we should divide echo spacing by acceleration factor (.53/2 for us). but i have found in a site that "Effective Echo Spacing (s) = 1/(BandwidthPerPixelPhaseEncode * MatrixSizePhase)" (1/(2200*64) for us). These two numbers are very different for us. what am i missing here?

ps. we have done a lot of fmap correction with .5ms for "Effective Echo Spacing". should we run our analysis with the new numbers? or the result would not be so much different