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<p class=MsoNormal><span lang=EN-US>Dear Donald,<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>I was wondering what the real probabilistic
part of SD_PROB is. The FOD glyphs themselves do not contain any true probabilistic
information: the lobes of these glyphs have certain widths because they are
only defined up until a certain resolution (a certain number of spherical
harmonics). The width of a lobe is therefore not a pure measure for the
uncertainty that a fiber population is oriented in that direction. To draw a
parallel with the diffusion tensor model: if we assume the main eigenvector e_1
of the DT gives the direction of the local fiber population, by bootstrapping
we can collect several e_1 estimates. If the direction of each e_{1,i} is given
by (\phi_i,\theta_i), we can uses these e_1 estimates to estimate P(\phi_i,\theta_i).
When doing fiber tracking, in every propagation step we choose a certain local
propagation direction (\phi_i,\theta_i) and we can calculate the product of P(\phi_i,\theta_i)
for all voxels i along the track to get a measure of the track probability. How
do this translate to fiber tracking based on CSD based FOD glyphs?<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>Best regards,<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>René Besseling<o:p></o:p></span></p>
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