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<p class="MsoNormal">Dear MRTrixers<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I am in the process of tracking the fornix in a large group of subjects. I mention large group because I am trying to find a way to track the fornix, without having to place to many post-hoc exclusion ROIs.<o:p></o:p></p>
<p class="MsoNormal">Currently I am using deterministic CSD (as recommended by Metzler-Baddeley et al, 2011/12), and I am placing a seed voxel in the mammillary bodies , and an inclusion see in the anterior hippocampus (there are additional parameters, please
see example below).<o:p></o:p></p>
<p class="MsoNormal">What I find is that this works great for some people, but others do not look great, and some don’t show up with anything. However, this latter group does indeed have a fornix (thankfully) when I use probabilistic tracking, but with many
other fibres of non-interest.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">The obvious question arises: am I doing this wrong, or do fornices really differ enough to warrant such a difference in appearance with this particular method?<o:p></o:p></p>
<p class="MsoNormal">And if I using a suboptimal procedure, does that mean that it is ok to do many post-hoc exclusion masks? I was hoping for a straightforward method that required few user input parameters as this may carry a large bias especially when I
will be tracking my patient group…<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Thank you!<o:p></o:p></p>
<p class="MsoNormal">zita<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">my code:<o:p></o:p></p>
<p class="MsoNormal">streamtrack SD_STREAM CSD4.mif -seed 1.81,3.76,-12.39,10 -initdirection 0,0,1 -include -20.88,-4.32,-13.39,10 -unidirectional -curvature 0.5 -mask mask.mif fornix_seedmb10_trghipp10_superiordir_unidir_curv0.5_csd_det.tck<o:p></o:p></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-GB">_________________________<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-GB">Eva Zita Patai<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-GB">Postdoctoral Research Associate<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-GB">UCL, Institute of Child Health<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-GB"><a href="mailto:e.patai@ucl.ac.uk">e.patai@ucl.ac.uk</a><o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-GB">020 7905 2730<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
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