<div dir="ltr"><div><div><div><div><div><div>Hi Marica,<br><br></div>This mailing list is dying a slow death... We've got a brand new website, <a href="http://www.mrtrix.org">www.mrtrix.org</a> , which comes with an equally brand new community forum: <a href="http://community.mrtrix.org">http://community.mrtrix.org</a><br></div>It'd be best to ask your question again over there: it's a better way of archiving questions/answers over time, so users can benefit and contribute more easily.<br><br></div>As a quick placeholder for an answer to your question: it is definitely expected that the response at b=1000 is much more "fat" (less disk-y) than the one at, e.g., b=3000. However, we've recently come across several less than optimal results from the dwi2response program ourselves, and in my personal opinion, these specific issues are only bound to get (much) worse at low b-values (we consider b=1000 to be a "low b-value"). That CSD still performs well, is rather related to the fact that CSD is quite resilient to small calibration errors of the response function... or at least if all you expect is a "relatively ok-ish" outcome. If you want the best outcome, it suddenly becomes much more important to nail that calibration. And even if your FODs are not *that* great, whole brain tracking might still look pretty fine after all, since tracking introduces extra constraints (e.g., curvature and minimum track length), that make it even harder to generate a majority of really wrong tracks.<br><br></div>So all in all: the tractogram has a tendency to (too) easily look "ok-ish". I'd say: head on over to the community forum at <a href="http://community.mrtrix.org">http://community.mrtrix.org</a> , and add a screenshot of your actual FODs (using the ODF display tool in mrview), and I'm sure you'll get some interesting feedback (and maybe spark a discussion or two ;-)).<br><br></div>Cheers,<br></div>Thijs<br><div><div><div><div><div><div><div><div class="gmail_extra"><br><div class="gmail_quote">On 23 February 2016 at 01:48, <a href="mailto:macara.p@libero.it">macara.p@libero.it</a> <span dir="ltr"><<a href="mailto:macara.p@libero.it" target="_blank">macara.p@libero.it</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div></div>Hi,<div><br></div><div>I would like to apply the constrained spherical deconvolution on my DTI dataset (30 directions, b=1000, 1 b0 image).</div><div>I tried to compute the response function with the command dwi2response an it gave me the response function I attached in this screenshot ("response.png").</div><div>Do you think it is correct? I have further run the CDS (dwi2fod) that gave me the image in my second screenshot ("CSD.png"). </div><div>I have also run the tractography (SD_stream) and it seems to me that it worked well ("tracto.png"), but I was wondering if doing the CSD makes sense given the type of data and the response function I get.</div><div><br></div><div>Thanks,</div><div>Marica</div><br>_______________________________________________<br>
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