<br><br><div class="gmail_quote">On Fri, Dec 3, 2010 at 11:02 AM, Katherine L. Ragland <span dir="ltr"><<a href="mailto:klragland@umc.edu" target="_blank">klragland@umc.edu</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Hello-<br>
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I am a fourth year medical student at the University of Mississippi Medical Center working with Dr. Judy James. We have been using your DTIStudio software for fiber tracking in the fetal brain. I would like to preface my questions by saying my current knowledge of DTI, eigenvalues, eigenvectors, etc. is quite limited. If I say something incorrectly, please let me know!<br>
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My questions for you deal with eigenvalues and eigenvectors.<br>
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1) What is the clinical applicability of these measurements? For example, does a shorter primary eigenvector signify a loss of anisotropy and possibly decreased myelination? What can one infer from increasing or decreasing trends in eigenvalues?<br>
<br></blockquote><div> I have some description about it in our Neuron paper (Mori and Zhang, 51, 527, 2006, Descriptions related to Fig. 10) and entire chapter 7 of my book "Introduction to Diffusion Tensor Imaging" is dedicated to this topic. </div>
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2) Do the eigenvalue 0 and eigenvector 0 correspond to the primary value/vector parallel to axon fibers?<br></blockquote><div><br></div><div>Correct.</div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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2) How do you calculate the primary eigenvector from the statistics derived from DTIstudio? (the 3 eigenvectors are given as x, y, and z coordinates)<br></blockquote><div><br></div><div>Not sure about your question. DtiStudio provides Eigenvector0, 1, 2, right? Are you asking how they are calculated internally? In DTI, the first thing we calculate is a 3x3 tensor, from which we can obtain 3 eigenvectors and 3 eigenvalues.</div>
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I appreciate any insight you can give.<br>
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Thank you very much for this software and your time in reading this.<br>
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Sincerely,<br>
<br>
Katie Ragland<br>
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