Or consider using a weight on your table in the lighter subjects Sent from a mobile device, please excuse my brevity/misspellings.
On Jul 14, 2013, at 10:07 PM, "Glasser, Matthew" <[email protected]> wrote: > I believe that comes from table vibration. You might consider increasing > the TR and it may be reduced. > > Matt. > > On 7/14/13 10:50 AM, "Andreas Bartsch" <[email protected]> wrote: > >> Hi, >> >> I have put my 1.8mm isotropic Trio diffusion protocol for download here: >> Archiv.zip <http://www.logicalenemy.net/data/wue/hcp/Archiv.zip> >> >> >> This is without GRAPPA but using the latest MB-GRAPPA reco refinements >> (cf. Steen Moeller's ISMRM poster this year) you may be able to use GRAPPA >> at an acceleration of 2, preferably with 72 reference lines, and cut down >> the TE to something like 73ms. >> I had observed a predominance of V1 RL/LR orientations (a "reddish >> bleeding" on the ColFA or dtifit V1/FA overlays) when using GRAPPA on our >> system. That does not seem to be completely resolved even though it has >> improved. It does not seem to affect probabilistic tractography with Xing >> fibers but it is the reason why I am still staying away from GRAPPA. >> >> Feedback and improvements are welcome, as is a notice and acknowledgement >> if you should use this for your studies. >> Cheers, >> Andreas >> >> >> Am 10.07.13 19:00 schrieb "[email protected]" unter >> <[email protected]>: >> >>> Send HCP-Users mailing list submissions to >>> [email protected] >>> >>> To subscribe or unsubscribe via the World Wide Web, visit >>> http://lists.humanconnectome.org/mailman/listinfo/hcp-users >>> or, via email, send a message with subject or body 'help' to >>> [email protected] >>> >>> You can reach the person managing the list at >>> [email protected] >>> >>> When replying, please edit your Subject line so it is more specific >>> than "Re: Contents of HCP-Users digest..." >>> >>> >>> Today's Topics: >>> >>> 1. Re: HCP-Users Digest, Vol 8, Issue 6 (Rei?-Zimmermann) >>> >>> >>> ---------------------------------------------------------------------- >>> >>> Message: 1 >>> Date: Tue, 9 Jul 2013 17:25:33 +0000 >>> From: Rei?-Zimmermann, Martin >>> <[email protected]> >>> Subject: Re: [HCP-Users] HCP-Users Digest, Vol 8, Issue 6 >>> To: Andreas Bartsch <[email protected]>, >>> "[email protected]" <[email protected]> >>> Message-ID: >>> <41e41d2635df1d4fb3430e087ba6f49328738...@s050003233.medizin.uni-leipzig >>> . >>> de> >>> >>> Content-Type: text/plain; charset="iso-8859-1" >>> >>> Great news! Thank you very much Andreas. >>> >>> Best, >>> Martin >>> ________________________________________ >>> Von: Andreas Bartsch [[email protected]] >>> Gesendet: Montag, 8. Juli 2013 22:16 >>> An: [email protected] >>> Betreff: Re: [HCP-Users] HCP-Users Digest, Vol 8, Issue 6 >>> >>> Hi, >>> >>> I can share a 1.8 mm isotropic mb-diffusion EPI from a 'standard' Trio. >>> Cheers, >>> Andreas Bartsch >>> >>> Am 08.07.13 19:00 schrieb "[email protected]" unter >>> <[email protected]>: >>> >>>> Send HCP-Users mailing list submissions to >>>> [email protected] >>>> >>>> To subscribe or unsubscribe via the World Wide Web, visit >>>> http://lists.humanconnectome.org/mailman/listinfo/hcp-users >>>> or, via email, send a message with subject or body 'help' to >>>> [email protected] >>>> >>>> You can reach the person managing the list at >>>> [email protected] >>>> >>>> When replying, please edit your Subject line so it is more specific >>>> than "Re: Contents of HCP-Users digest..." >>>> >>>> >>>> Today's Topics: >>>> >>>> 1. Re: HCP-dMRI gradient table on a TRIO - any experience? >>>> (Harms, Michael) >>>> >>>> >>>> ---------------------------------------------------------------------- >>>> >>>> Message: 1 >>>> Date: Mon, 8 Jul 2013 14:44:26 +0000 >>>> From: "Harms, Michael" <[email protected]> >>>> Subject: Re: [HCP-Users] HCP-dMRI gradient table on a TRIO - any >>>> experience? >>>> To: Rei?-Zimmermann, Martin >>>> <[email protected]>, "Xu, Junqian" >>>> <[email protected]> >>>> Cc: "[email protected]" <[email protected]> >>>> Message-ID: <ce003573.1b7fe%[email protected]> >>>> Content-Type: text/plain; charset="iso-8859-1" >>>> >>>> >>>> Hi Martin and Satra, >>>> The HCP itself has not extensively evaluated a 1.5 mm multiband DWI >>>> acquisition on the Trio platform, so we don't have anything concrete to >>>> share at this time. Perhaps we should rephrase that sentence in the >>>> Appendix I release guide, but it was included primarily to encourage >>>> individuals on other platforms to pilot beyond the "standard" 2 mm >>>> resolution. >>>> >>>> I'd encourage you to start by piloting ~1.8 mm isotropic on Trio/Verio >>>> scanners with a multiband factor of 3-4. >>>> >>>> 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 >>>> St. Louis, MO 63110 Email: [email protected] >>>> >>>> >>>> >>>> >>>> On 7/7/13 10:46 AM, "Rei?-Zimmermann, Martin" >>>> <[email protected]> wrote: >>>> >>>>> Hello Gordon, >>>>> >>>>> thank you very much for your answers. Due to our resolution limited to >>>>> 2 >>>>> mm isotropic we have a substantial lower TR (3270 vs. HCP 5520 ms) and >>>>> a >>>>> TE of 110.4 ms (HCP 89.50 ms). I wasn't sure if it is the one gradient >>>>> direction that needs to be changed (since it always stopped at the same >>>>> point) or something else (in this case using a longer TR/TE). >>>>> Thanks to your answer, I will now gradually increase TR in a >>>>> trial-and-error-fashion. >>>>> >>>>> Any chance, the mentioned 1.5mm-DTI-TRIO-sequence can be posted here? >>>>> (I >>>>> guess, there are a couple more TRIO users in the mailing list) >>>>> >>>>> Best regards, >>>>> Martin >>>>> >>>>> >>>>> ________________________________________ >>>>> Von: Xu, Junqian [[email protected]] >>>>> Gesendet: Samstag, 6. Juli 2013 16:57 >>>>> An: Rei?-Zimmermann, Martin >>>>> Cc: [email protected] >>>>> Betreff: Re: [HCP-Users] HCP-dMRI gradient table on a TRIO - any >>>>> experience? >>>>> >>>>> Martin, >>>>> >>>>> Sorry that I misunderstood your problem. However It is still gradient >>>>> duty cycle related. The Siemens VB software version doesn't estimate >>>>> gradient heating as accurately/conservatively as the Siemens VD >>>>> software >>>>> version. Hence the minimum TE/TR allowed by the sequence can still trip >>>>> the gradient duty cycle limit in real time, causing scan crash. >>>>> >>>>> The solution is to relax the TE/TR little by little with try-and-error >>>>> until you find a stable combination that passes your test. >>>>> >>>>> Gordon >>>>> >>>>> On Jul 5, 2013, at 9:12 PM, "Xu, Junqian" <[email protected]> wrote: >>>>> >>>>>> Martin, >>>>>> >>>>>> The culprit is the gradient power amplifier (GPA) duty cycle too high >>>>>> on the Y axis (i.e. the consecutive high value of 0.992 and -0.975). >>>>>> We >>>>>> have encountered similar problem in HCP and have implemented a >>>>>> solution >>>>>> to solve the gradient duty cycle issue. >>>>>> >>>>>> You can find the solution to this problem in Sotiropoulos et al. >>>>>> NeuroImage special issue >>>>>> >>>>>> http://www.ncbi.nlm.nih.gov/pubmed/23702418 >>>>>> >>>>>> Section: Q-space sampling >>>>>> >>>>>> "However, even when realistic sequences of diffusion gradient >>>>>> orientations were used (even with interleaved shells), the gradient >>>>>> duty >>>>>> cycle, due to accumulated heating, could still limit the achievable >>>>>> minimal TR. The order of the diffusion gradient orientations in the >>>>>> final HCP dMRI protocol was therefore optimised by swapping adjacent >>>>>> orientations to reduce the auto-correlation (lag = 1) of absolute >>>>>> gradient amplitude (~ < 0.5) for each physical gradient axis." >>>>>> >>>>>> Please let me know if this is clear enough for you to solve your >>>>>> specific case. >>>>>> >>>>>> Regards >>>>>> Gordon >>>>>> >>>>>> On Jul 5, 2013, at 11:06 AM, "Rei?-Zimmermann, Martin" >>>>>> <[email protected]> wrote: >>>>>> >>>>>>> Dear all, >>>>>>> >>>>>>> I tried implementing and converting the HCP dMRI-sequences for our >>>>>>> TRIO. I followed the suggestions in the Appendix I and with minor >>>>>>> modifications (2 mm isotropic) it works well with MB3 and the >>>>>>> MDDW-gradient table (60 directions). >>>>>>> >>>>>>> However, when I use the HCP gradient table the measurement stops at >>>>>>> reproducable stops within the sequence (see following) and always >>>>>>> with >>>>>>> the same error (hope I can translate that somehow from German into >>>>>>> English): >>>>>>> Error in gradient amplifier, GPA not ready. duty cycle is to high. >>>>>>> Please check sequence parameters. >>>>>>> >>>>>>> The sequences always stop at these points: >>>>>>> >>>>>>> 95dir-dMRI: direction number 47 (-1.000 , -0.001 , -0.011) >>>>>>> 96dir-dMRI: direction number 75 (-0.094 , 0.992 , -0.082) >>>>>>> 97dir-dMRI: direction number 55 (-0.134 , -0.975 , 0.180) >>>>>>> >>>>>>> The images before look great! >>>>>>> >>>>>>> I took a look at the page of Emmanuel Caruyer - but if I create a >>>>>>> gradient table of 90 dir (the HCP 96dir-table seems to have 6 b0 and >>>>>>> the rest b1000-3000, the E.C.-table seems to encode b>0 values, >>>>>>> right?) >>>>>>> it is totally different from the HCP one. >>>>>>> >>>>>>> I also read the note in the HCP gradient table that these gradients >>>>>>> are customized for the Connectome-Scanner. >>>>>>> >>>>>>> So my question is: Shall I just use one created on Emmanuel's page >>>>>>> or >>>>>>> can I (or better: someone else) change the one from HCP? >>>>>>> >>>>>>> The Appendix I also mentions that the dMRI-sequence has been >>>>>>> successfully tested on a TRIO and Verio with 1.5 mm isotropic >>>>>>> resolution (and b2000). Is it possible that you could post the >>>>>>> protocol >>>>>>> (including the gradient table). >>>>>>> >>>>>>> Thank you very much. Best regards, >>>>>>> Martin >>>>>>> ____________________________________________________ >>>>>>> Dr. med. Martin Reiss-Zimmermann >>>>>>> Abteilung f?r Neuroradiologie >>>>>>> Universit?tsklinikum Leipzig A?R >>>>>>> Liebigstr. 20 >>>>>>> 04103 Leipzig >>>>>>> >>>>>>> Mail: [email protected] >>>>>>> Fon: +49 - 341 - 97 17 585 >>>>>>> Fax: +49 - 341 - 97 17 490 >>>>>>> Net: http://www.neuroradiologie-leipzig.de >>>>>>> >>>>>>> ..................................................................... >>>>>>> . >>>>>>> . >>>>>>> . >>>>>>> ..................................................................... >>>>>>> . >>>>>>> . >>>>>>> . >>>>>>> ........................................................ >>>>>>> Universit?tsklinikum Leipzig - Anstalt ?ffentlichen Rechts | >>>>>>> Aufsichtsratsvorsitzender: Prof. Dr. Wolfram Knapp >>>>>>> Medizinischer Vorstand und Sprecher: Prof. Dr. med. Wolfgang E. >>>>>>> Fleig >>>>>>> | Kaufm?nnischer Vorstand: Dipl.-Kfm. 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