Dear Tom, I have a question regarding the --acqp file to run eddy in FSL. On the webpage, it says that if we know the phase encoding direction (A>P), echo spacing (0.8) and EPI factor (128), we can then create the --acqp file and calculate its last number as 0.8*0.001*127 = 0.102. I don't understand what this last number represents and why we should multiply the echo spacing (0.8) by 0.001 and 127 (i assume this last number is the EPI factor - 1?). what we want is the time between acquiring the centre of the first echo and acquiring the centre of the last echo. The 0.001 is to convert the echo-spacing of 0.8ms to 0.0008s. The 128-1 is because there are 127 “echo spacings” between the 128 echoes. Hope that helps. Jesper I would be very grateful if someone could explain this to me! Thank you so much! ________________________________ To unsubscribe from the FSL list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=FSL&A=1 ######################################################################## To unsubscribe from the FSL list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=FSL&A=1