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<TITLE>RE: Mrtrix tractography questions</TITLE>
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<FONT FACE="Helvetica, Verdana, Arial"><SPAN STYLE='font-size:11pt'>Hello Donald et al,<BR>
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We have a couple of questions regarding the tractography mechanics involved in MRtrix<BR>
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1. How does Mrtrix start sampling tracts from ROI’s? That is, if you provide an ROI how does MRtric decide where to start the tract from? From the boundary of the ROI or from the centre? Do you take into account if the ROI overlaps grey and white matter? <BR>
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2. We are also interested in your thoughts on putting a “weighting” on tract length. <BR>
A number of studies suggest that if were using a simple deterministic tracking algorithm to measure connections between multiple ROI’s we should weigh long tracts since there is bias towards longer tracts. Does the same apply for your algorithms? We were even suspecting that using the probabilistic tracking option there would be bias against longer tracts? <BR>
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cheers<BR>
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Marc<BR>
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</SPAN></FONT><BLOCKQUOTE><SPAN STYLE='font-size:11pt'><FONT COLOR="#0080FF"><FONT FACE="Calibri, Verdana, Helvetica, Arial"><B>Marc Seal<BR>
</B></FONT></FONT><FONT FACE="Calibri, Verdana, Helvetica, Arial"><B><FONT COLOR="#000080">Group Leader, Developmental Imaging, Murdoch Childrens Research Institute<BR>
Senior Research Fellow, Department of Paediatrics, The University of Melbourne<BR>
<BR>
</FONT></B>The Royal Children's Hospital, Flemington Road, Parkville, Victoria 3052, Australia<BR>
M 0423 606 185 | T +61 3 9345 4310 | F +61 3 9345 4325 <BR>
E <a href="marc.seal@mcri.edu.au">marc.seal@mcri.edu.au</a><BR>
www.mcri.edu.au<BR>
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</FONT></SPAN><FONT COLOR="#008000"><FONT SIZE="1"><FONT FACE="Webdings"><SPAN STYLE='font-size:9pt'></SPAN></FONT></FONT></FONT><FONT SIZE="1"><FONT FACE="Webdings"><SPAN STYLE='font-size:9pt'> </SPAN></FONT><SPAN STYLE='font-size:9pt'><FONT COLOR="#009C65"><FONT FACE="Arial">Please consider the environment before printing this email<BR>
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