I believe the magnitude image is used only for masking, if that helps - you could use another similar image perhaps ________________________________________ From: FSL - FMRIB's Software Library [[log in to unmask]] on behalf of Suchada Tantisatirapong [[log in to unmask]] Sent: Monday, December 05, 2011 2:06 PM To: [log in to unmask] Subject: [FSL] Fieldmap Hello, I'm trying to unwrap EPI using FUGUE. I have only a single phase map and no magnitude map. I'm wondering if I can use T1 or T2 image as a magnitude map. Could any one please clarify how to calculate the magnitude fieldmap ? Thank you very much and regards, Suchada The information in this e-mail is intended only for the person to whom it is addressed. If you believe this e-mail was sent to you in error and the e-mail contains patient information, please contact the Partners Compliance HelpLine at http://www.partners.org/complianceline . If the e-mail was sent to you in error but does not contain patient information, please contact the sender and properly dispose of the e-mail.