Thanks for that reply, Micahel. Exactly, what I plan to do for diffusion protocol.
Just wondering though on your or anyone else's suggestion on running BOLD with MB>2. Thanks Regards --VM On Wed, Dec 7, 2016 at 10:50 AM, Harms, Michael <mha...@wustl.edu> wrote: > > Hi, > It appears that you are trying to replicate the basics of one of our > Lifespan pilot protocols on a Skyra — i.e., 1.5 mm voxels with 20 total min > of dMRI scanning. But due to the longer TE and longer TR (resulting in > fewer total directions), you are definitely going to have worse overall SNR > than what we achieved. We highly suggest that you collect some pilot data > to assess the quality of your proposed dMRI protocol with your end-measures > of interest, including possibly a comparison against a protocol with larger > voxels (e.g., 1.7-1.8 mm voxels) that would recover some SNR. > > cheers, > -MH > > -- > Michael Harms, Ph.D. > ----------------------------------------------------------- > Conte Center for the Neuroscience of Mental Disorders > Washington University School of Medicine > Department of Psychiatry, Box 8134 > 660 South Euclid Ave. Tel: 314-747-6173 <(314)%20747-6173> > St. Louis, MO 63110 Email: mha...@wustl.edu > > From: <hcp-users-boun...@humanconnectome.org> on behalf of "Glasser, > Matthew" <glass...@wustl.edu> > Date: Wednesday, December 7, 2016 at 11:49 AM > To: "hcp-users@humanconnectome.org" <hcp-users@humanconnectome.org> > Subject: [HCP-Users] FW: Skyra - BOLD and diffusion MRI protocols > > > > From: Matt Glasser <glass...@wustl.edu> > Date: Wednesday, December 7, 2016 at 10:14 AM > To: neuroimage analyst <neuroimage.anal...@gmail.com> > Subject: Re: [HCP-Users] Skyra - BOLD and diffusion MRI protocols > > I wouldn’t acquire multiple repetitions of the same directions, but rather > more unique directions. If necessary you can acquire the DWIs with only a > single phase encoding direction in an effort to get more unique diffusion > directions, but it is important that you get phase reversed b0 images. > > As for the MB error, I don’t know how to fix it, but you should definitely > be able to do better than MB=2 with a 32 channel head coil. Hopefully > someone else on the list knows how to fix this. > > Peace, > > Matt. > > From: neuroimage analyst <neuroimage.anal...@gmail.com> > Date: Tuesday, December 6, 2016 at 8:54 PM > To: Matt Glasser <glass...@wustl.edu> > Subject: Re: [HCP-Users] Skyra - BOLD and diffusion MRI protocols > > Hi Matt, > > 32 channel head coil. > > I was able to run the diffusion sequence on a phantom when TR/TE was > 7000/106 ms. Since the scan time with this tr is already 20 minutes, I was > thinking to acquire just b0 with PA phase encoding and the other 64 > directions 2b data+b0 with AP. will that be okay? my concern is snr at te > will not be very good and data may not be too great and may be atleast 2 > reps are desired? > > Thanks > > Regards > > -VM > > On Dec 6, 2016 6:46 PM, "Glasser, Matthew" <glass...@wustl.edu> wrote: > >> What coil are you using? >> >> Peace, >> >> Matt. >> >> From: <hcp-users-boun...@humanconnectome.org> on behalf of neuroimage >> analyst <neuroimage.anal...@gmail.com> >> Date: Tuesday, December 6, 2016 at 11:56 AM >> To: "hcp-users@humanconnectome.org" <hcp-users@humanconnectome.org> >> 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 >> HCP-Users@humanconnectome.org >> 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. >> > > ------------------------------ > > 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 > HCP-Users@humanconnectome.org > 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 > HCP-Users@humanconnectome.org > http://lists.humanconnectome.org/mailman/listinfo/hcp-users > _______________________________________________ HCP-Users mailing list HCP-Users@humanconnectome.org http://lists.humanconnectome.org/mailman/listinfo/hcp-users
