Thank you for the response. I do not believe it has background suppression - is there a way to directly determine this from the data? If there wasn't background suppression, how could I use the raw ASL data for calibration? Thanks, Danielle ######################################################################## To unsubscribe from the FSL list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=FSL&A=1