I think duty cycle issues are a bigger deal for long diffusion scans. I’ll note that if this is resting state data subjects may be likely to fall asleep with long scans, which will cause significant changes in functional connectivity.
Peace, Matt. From: <[email protected]<mailto:[email protected]>> on behalf of "Mark A. Pinsk" <[email protected]<mailto:[email protected]>> Date: Thursday, October 19, 2017 at 1:48 PM To: "[email protected]<mailto:[email protected]>" <[email protected]<mailto:[email protected]>> Subject: [HCP-Users] question re: collecting long duration BOLD EPI scans Hi all, We have several investigators here that would like to collect multi band BOLD EPI runs of very long duration (~1 hour). First, we found that the product Siemens SMS sequence limits you to 35 min 47 sec. Once your # measurements exceeds that duration, the TA changes to show >=24 hours and refuses to run. Has anyone noticed this or found a workaround? Second, it appears that the CMRR SMS sequence does not have this limitation. So we were planning on recommending that those users who want to collect very long EPI runs use the CMRR sequence. Can we expect increases in thermal noise or any other duty-cycle related issues that might reduce SNR progressively over time? And should we be concerned at all about increased wear on the gradient coils or other hardware if we don't allow it to cool down more frequently? Thanks ahead for any advice! Mark _______________________________________________ HCP-Users mailing list [email protected]<mailto:[email protected]> http://lists.humanconnectome.org/mailman/listinfo/hcp-users _______________________________________________ HCP-Users mailing list [email protected] http://lists.humanconnectome.org/mailman/listinfo/hcp-users
