Hi Venkat,<br><br>After fiber tracking, it is a common practice to quantify the results. For the quantification, the streamline information of the tractography needs to be converted to pixel information. For this conversion, the simplest way is to use 1/0 binarilzation. If a pixel contains a streamline, it becomes 1 and if not, remains 0. This is basically a masking, which can be applied to, for example, a FA map and get a FA value of the tract. You can also count the number of pixels with "1" and use it as the tract volume.<br>
<br>One problem of this simple approach is that even if a pixel contains 10 streamlines, the pixel becomes "1", which is the same as another pixel that contains only 1 streamline. Namely, during the binalization, information about the density of the streamline is lost. I believe (Hangyi, please correct me if I'm wrong) "fiber density map" tells how many streamlines were there in each pixel. You can potentially use it to get, for example, density-weighted FA value, in which pixels that contain more streamlines are more weighted than those contain only 1 streamline.<br>
<br><div class="gmail_quote">On Fri, Jul 23, 2010 at 6:19 PM, Rajagopalan, Venkateswaran <span dir="ltr"><<a href="mailto:rajagov2@ccf.org" target="_blank">rajagov2@ccf.org</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
<div>
<br>
<p><font size="2">Dear All,<br>
<br>
I am using DTIstudio_latest_x86.exe after fiber tractography I notices a new option named "save fiber density map" (normalized and non normalized). I am wondering what information does this fiber density map convey and how this information can be used for instance to compare between two groups. How the map is normalized.<br>
<br>
Thanks<br>
<br>
Venkat</font>
</p>
<p></p><pre>===================================
<p class="MsoNormal"><font size="5" color="green" face="Webdings"><span style="font-size: 18pt; font-family: Webdings; color: green;">P</span></font><font size="2" color="navy" face="Calibri"><span style="font-size: 10pt; font-family: Calibri; color: navy;"> </span></font><font size="1" color="green" face="Arial"><span style="font-size: 7pt; font-family: Arial; color: green;">Please consider the environment before printing this e-mail</span></font></p>
Cleveland Clinic is ranked one of the top hospitals
in America by U.S.News & World Report (2009).
Visit us online at <a href="http://www.clevelandclinic.org" target="_blank">http://www.clevelandclinic.org</a> for
a complete listing of our services, staff and
locations.
Confidentiality Note: This message is intended for use
only by the individual or entity to which it is addressed
and may contain information that is privileged,
confidential, and exempt from disclosure under applicable
law. If the reader of this message is not the intended
recipient or the employee or agent responsible for
delivering the message to the intended recipient, you are
hereby notified that any dissemination, distribution or
copying of this communication is strictly prohibited. If
you have received this communication in error, please
contact the sender immediately and destroy the material in
its entirety, whether electronic or hard copy. Thank you.
</pre></div>
<br>_______________________________________________<br>
mristudio-users mailing list<br>
<a href="mailto:mristudio-users@mristudio.org" target="_blank">mristudio-users@mristudio.org</a><br>
<a href="http://lists.mristudio.org/mailman/listinfo/" target="_blank">http://lists.mristudio.org/mailman/listinfo/</a><br>
Unsubscribe, send a blank email to: <a href="mailto:mristudio-users-unsubscribe@mristudio.org" target="_blank">mristudio-users-unsubscribe@mristudio.org</a><br>
<br></blockquote></div><br>