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. Ekkehard Zimmer >>>> Sitz: Liebigstra?e 18, 04103 Leipzig | Telefon +49-341-971709 | >>>>St.Nr.: 23114904074 | IK: 261401052 >>>> Bankverbindung: Deutsche Bank | BLZ: 86070000 | Kto.: 1247998 | >>>>Swift-Code: DEUTDE8L | IBAN: DE27860700000124799800 >>>> Internet: www.uniklinikum-leipzig.de >>>> >>>> Universit?t Leipzig | Ritterstr. 26, 04109 Leipzig | K?rperschaft des >>>>?ffentlichen Rechts | Vertreten durch die Rektorin Prof. Dr. Beate >>>>Sch?cking >>>> Zust?ndige Aufsichtsbeh?rde: SMWK, Wigardstr. 17, 01097 Dresden, >>>>www.smwk.de >>>> Umsatzsteuer-Identifikationsnummer gem?? ?27a Umsatzsteuergesetz DE >>>>141510383 >>>> >>>> Diese E-Mail enth?lt vertrauliche und/oder rechtlich gesch?tzte >>>>Informationen. Sollten Sie nicht der richtige Empf?nger sein oder Sie >>>>haben diese E-Mail irrt?mlich erhalten, informieren Sie uns bitte >>>>sofort und vernichten diese E-Mail. 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