What coil are you using? Peace,
Matt. From: <[email protected]<mailto:[email protected]>> on behalf of neuroimage analyst <[email protected]<mailto:[email protected]>> Date: Tuesday, December 6, 2016 at 11:56 AM To: "[email protected]<mailto:[email protected]>" <[email protected]<mailto:[email protected]>> Subject: [HCP-Users] Skyra - BOLD and diffusion MRI protocols Hi, HCP Users and Developers. We have been trying to build a protocol for BOLD and DWI on our Skyra (VE11C) using the latest release of HCP pulse sequences. But we haven't been completely successful with what we wanted to achieve. A) BOLD: We were hoping to get a TR in the range of 750ms, res = 2mm3, echo spacing (ES) approx 0.65. We were able to get to echo spacing of 0.69 and all the other parameters with MB = 8. However, the sequence doesn't run and it gives us "Max amplitude overflow on gradient z axis" after MB factor exceeds 2. It appears to me that then we have to sacrifice TR and only run with MB = 2. Is there anybody with a Skyra who has able to achieve what we are hoping for and willing to share the protocol with us? OR if somebody could guide us to resolve the error of amplitude overflow. B) DWI: The idea was to have res = 1.5mm3, 2b-values at 1000 and 2500, 64 directions with the best BW and ES achievable. The sequence runs for 7 minutes out of total 13 minutes and gives gradient power amplifier error. On Michael Harms's suggestion, I adjusted flip angle to 78/160 at a TR of 5500 ms with excite/refocus pulse duration of 3840 and 7680. there was a pop up warning that RF is clipped and the maximum refocusing angle was 142 instead of 160. I placed a 64 directions diffusion vector and ran the sequence under "free" mode. Again, I will appreciate if there is anybody with a Skyra who has able to achieve what we are hoping for and willing to share the protocol with us, along with the diffusion vector sets? OR if somebody could guide us to resolve the error. Thank you. Regards --VM _______________________________________________ HCP-Users mailing list [email protected]<mailto:[email protected]> http://lists.humanconnectome.org/mailman/listinfo/hcp-users ________________________________ The materials in this message are private and may contain Protected Healthcare Information or other information of a sensitive nature. If you are not the intended recipient, be advised that any unauthorized use, disclosure, copying or the taking of any action in reliance on the contents of this information is strictly prohibited. If you have received this email in error, please immediately notify the sender via telephone or return mail. _______________________________________________ HCP-Users mailing list [email protected] http://lists.humanconnectome.org/mailman/listinfo/hcp-users
